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General Category => General Discussion => Topic started by: SED on December 29, 2014, 12:49:01 PM

Title: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 12:49:01 PM
Thought this might be helpful.  And it will help me remember the next time I get into the bevel drive. ;)  Hope you find it useful.
I'm definitely inspired by photo essays of Chuck in Indiana  ;-T

You will need a small 2 or 3 jaw puller - otherwise pretty standard tools.

Problem-Gear oil from the rear drive was coating the drive side of the brake disk and dripping down the wheel when parked.  Seal (arrow S below) was leaking.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/DiagSeal_zps16cda2eb.jpg)

Put bike on center stand and secure it by looping a tie-down strap behind the stand and through the front wheel (or to your lift) - you'd hate to push the bike forward off the stand:
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1180_zpsa7aaa543.jpg)

Remove top mount of rear shocks (allows the swing arm to move up and down giving access to rear axle).
Remove rear axle and rear wheel.
Remove 2 brake caliper mounting bolts.
I chose to remove the bevel box from the swingarm rather than mess with the boot between the swingarm and gearbox.  Loosen the 4 acorn nuts that join the bevel box to the swingarm and pull to the rear.  Note: the pinion bearing holder is pinched between the bevel box and the swingarm and could pull out or fall out.  Also there is a coupling, a spline adapter and a small spring that will probably slide out of the swingarm as the bevel box is removed.

This is quick.  The first picture below was taken at 6:02 and the second at 6:11.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1181_zpscf4688a2.jpg)

9 minutes later:
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1182_zps89a1017f.jpg)
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 12:57:56 PM
Next pull the rear shock off the bevel box.  Clamp the disk with soft jaws and remove the bolts that hold the disk.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1183_zpsb5d967bc.jpg)

Slide pinion shaft and bearings out of bevel box and wrap in a nice clean towel for safe keeping.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1184_zps19fb72fe.jpg)

Remove axle spacer.  This one was stuck and had to be loosened by tapping from the side with a rubber hammer.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1186_zps53ed467a.jpg)

Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 01:21:53 PM
Fold back the lock tabs and remove the 7 bolts that hold the back of the box from the aluminum housing.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1185_zps833016f0.jpg)

The housing with the back removed.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_2788_zpsdccb72dd.jpg)

Between the housing and back plate is a shim and some very thin gaskets (H & I below) that set the spacing between the ring and pinion.  I assumed that they were set correctly and did not disturb them.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/DiagSpacer_zpse50afab1.jpg)

Two things to check:  First that the nose of the housing has an oil passage that carries gear lube between the pinion bearings like this.  (hole near top of photo looking in the nose of the housing) If yours does not, Chuck from Indiana has a great photo tutorial of it here on WG.  This passage was drilled with Chuck's help.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_2791_zps0d967ae1.jpg)

Second, check that the bevel drive has Schnorr washers (1st picture) and does not have the "lock plates" (second picture).  Apparently the lock plates don't lock, and they are too thick to fold over as locking tabs and they have been known to allow the bolts to back out of the ring gear.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1188_zps96082f5c.jpg)

Bad "Lock Plates"
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_2781_zps489de070.jpg)
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 01:41:03 PM
Forgot to mention that when you pull the back of the bevel box off there is a roller bearing that may stay with the housing or come out with the back.  It is shown here:
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_2792_zpse4eb8f69.jpg)

Protect it with a clean rag.

Also there is a small seal (AB in the parts diagram above) that rides outside the bearing on the rusty nose at the top of the picture (arrow).  The seal is down in the housing and should be checked that it  is still in good condition.  

(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1187mod_zps32b5e182.jpg)
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 02:00:57 PM
There is a circlip that holds the inner race on the nose of the "hollow shaft".  (The hollow shaft holds the ring gear and the bearings that drive the rear wheel.  It is labeled D in the parts diagram above.)
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1188_zps96082f5c.jpg)

The race may need to be driven onto the shaft more to expose the circlip.  Light tapping with a mild steel punch works.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1187_zps16ca83ca.jpg)

Before pulling the inner race clean up the nose of the hollow shaft to make it easier for the inner race to come off - Arrow:
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1187mod_zps32b5e182.jpg)

A small puller is probably the only special tool needed.  The jaws grab under the 2 washers below the inner race.  I was concerned the washers would be bent by the pull, but the inner race was not too tight on the hollow shaft.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1190_zps501be9e9.jpg)

Clamp the hollow shaft in the vice using soft jaws and remove the 6 ring gear bolts and their Schnorr washers.  They should be held in by locktite.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1191_zpscfff05d4.jpg)

Title: Re: Rear bevel drive seal replacement (small block)
Post by: sib on December 29, 2014, 02:14:40 PM
Second, check that the bevel drive has Schnorr washers (1st picture) and does not have the "lock plates" (second picture).  Apparently the lock plates don't lock, and they are too thick to fold over as locking tabs and they have been known to allow the bolts to back out of the ring gear.

The parts manual blowup pic and the parts table for the '13 V7 series show neither Schnorr washers nor lock plates under the bolts.  The workshop manual mentions "safety plates" but none of the pics show them.  What gives?
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 02:20:38 PM
This is where I departed from the Guzzi workshop book:
Guzzi says tap out the hollow shaft with a plastic mallet - I think they mean Rubber mallet.  It didn't work.

Instead heat the bearing and back plate with a hairdryer  :wife:  then turn it over and bang the nose of the hollow shaft down on a nice block of wood.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1192_zps21570061.jpg)

(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1195_zps696eee92.jpg)

And Bob's your uncle.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1194_zps90c20f59.jpg)
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 02:24:06 PM
The parts manual blowup pic and the parts table for the '13 V7 series show neither Schnorr washers nor lock plates under the bolts.  The workshop manual mentions "safety plates" but none of the pics show them.  What gives?

I should say that this is for a 1981 Monza.  I've read on WG that the lock plates were a problem and that Schnorr washers and lock tight the solution, but I don't know when Guzzi changed things.  They may be using just bolts and locktite now.
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 02:28:51 PM
Should also say what workshop manuals I'm referring to!
1983 V50III etc. from Gregory Bender's website:
http://www.thisoldtractor.com/mg_manuals/workshop_manual_v35-ii_v50-iii_v35-imola_v50-monza_v35c_v50c_v65_v65sp_en.pdf

And the 2003 Breva manual from Guzzitek:
http://www.guzzitek.org/gb/ma_us_uk/750/Breva750IE_042003_Atel(GB).pdf

Both sites are excellent resources - thanks to their owners!
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Chuck in Indiana on December 29, 2014, 02:39:15 PM
Thanks for that, SED. Attaboy. ;-T We're beginning to get some small block stuff documented here. I wish someone would do the transmission..
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 02:44:17 PM
The seal presses into one side of the backplate and the bearing the other.  I tried to pry them apart like this and ended up scaring the aluminum backplate   :'(  so don't do this:
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1198_zpsbe4246e7.jpg)
Perhaps you can put a drift through the bearing to drive out the seal (Guzzi says to drive out seal first), but the bearing ID is smaller than the seal ID.

I heated the backplate with the hairdryer  :wife: and bearing came out easy.  I used a sharpie to mark the bearing so it could be put back the same way.  This shows the backplate ready for the new seal.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1202_zpse35397da.jpg)

BTW - the bearing (U in the parts diagram) is 70x110x13 16014 SKF and can be found on the internet for reasonable prices.  This is for an early '80s small block - don't know if the modern bikes are the same.

The cause of the seal failure was corrosion on the hollow shaft.(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1197_zpsa1374364.jpg)

Cleaned up sealing surface with 400 grit wet or dry.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1200_zps44fafb7f.jpg)
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 02:46:26 PM
Thanks for that, SED. Attaboy. ;-T We're beginning to get some small block stuff documented here. I wish someone would do the transmission..

Thanks Chuck.  Love your work.  And that Aero engine is cool!
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 02:47:36 PM
OK - gotta run some errands, so more pictures later.

Hope you like it so far.
Shawn
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Chuck in Indiana on December 29, 2014, 03:19:25 PM
OK - gotta run some errands, so more pictures later.

Hope you like it so far.
Shawn

Absolutely. I found that if you use the hair dryer :wife: or industrial heat gun here, it takes very little to pull the race.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1190_zps501be9e9.jpg)
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 29, 2014, 07:33:07 PM
So I cleaned all the parts.  (I use hot water and powdered laundry detergent for everything I can submerge)
Reassembly is reverse of disassembly according to Guzzi so I installed the seal and then heated the backplate and installed the bearing.  

Driving the seal into the backplate with large blocks of wood distributes the force so the large seal isn't dimpled.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1201_zpscc1a7d48.jpg)

Warm the backplate and push the bearing in the same way, then seated the outer race in the backplate with a soft punch.  Unfortunately I did not take pictures of most of the reassembly.

Pre-lube the bearing and sealing surfaces.

Warmed the bearing and backplate assembly with the :wife: and pushed the hollow shaft though the warm bearing with wooden blocks and seated the inner race on the hollow shaft with the soft punch.  No picture, but if you've been following along in the Breva workshop book you'll find an error at this step - the picture and instructions marked with the red arrow should be on the next page.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/BrevaWorkshopError_zpsec98f07d.jpg)

There is another interesting error: driving the hollow shaft into the bearing has a tendency to push the bearing back out of the back plate (there is no circlip holding it in) - so once you are sure the bearing is seated on the shaft, go back and make sure it is still seated in the backplate.  If not the hollow shaft will not turn easily when the backplate and bevel housing are bolted together again.

  
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 30, 2014, 01:50:24 PM
Once the hollow shaft and bearing have been seated the next step is to reinstall the ring gear.  The recommendation has been to use locktite and Schnorr washers and torque to 40-42 Newton/meters.

Then install the two washers (larger first - P & O in the diagram) and inner race (M) onto the hollow shaft (I had to tap the inner race with a soft drift) followed by the circlip (L).
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/Diagram_zpse728b8ed.jpg)

Pre-lube the roller bearing(N), small seal (AB) and ring gear and assemble the back plate to the housing with the shim (arrow I in diagram) and gaskets (H) between them.  I assumed the ring and pinion clearance was set correctly so did not change the shims or gaskets.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/DiagSpacer_zpse50afab1.jpg)

If the hollow shaft gets more difficult to turn as the bolts get tight it may mean that the hollow shaft is not seated in the bearing (U) or the bearing not seated in the backplate.

Re-insert the pinion into the bevel box making sure the oil holes in the pinion housing (L below) are aligned top and bottom when assembled on the bike.  Put the acorn nuts on the studs to keep it from accidentally dropping out  ::)  I installed the pinion before attaching the brake disk to minimize the chance of dirt entering the bevel box. 
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/DiagPinionOil_zps305084de.jpg)


Note that the nuts (T in top diagram) must be seated in their recesses in the backplate before the brake disk can be installed. 

Grease the coupling and spline adapter (L, M, N, O and P below) and make sure the little spring sits in the recess of driveline (C) and they bevel box should bolt right up.  Make sure the axle spacer is installed before installing the axle.  Dave Richardson suggests leaving the 4 nuts loose until the axle is installed and tightened so that it is aligned with the axle shaft.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/DiagSwingArm_zpsf18d6cb3.jpg)

Arrows show the spacers and gaskets in the installed drive.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1204mod_zps324d4c08.jpg)

Support the swingarm so that it is level and fill to the level plug with the appropriate lube. 
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1203_zps92dadad3.jpg)

Bolt all the rest of the goodies together, check your tire pressure and go for a test ride. ;D

Hope this has been helpful.  And if you have any additional recommendations I'd love to hear them.
Shawn








Title: Re: Rear bevel drive seal replacement (small block)
Post by: Mayor_of_BBQ on December 30, 2014, 02:03:13 PM
Very nicely done! :clap


Sent from my iPhone using Tapatalk
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 30, 2014, 02:14:54 PM
Absolutely. I found that if you use the hair dryer :wife: or industrial heat gun here, it takes very little to pull the race.
(http://i305.photobucket.com/albums/nn233/shawnsci/MonzaBevelDrive/IMG_1190_zps501be9e9.jpg)

Thanks for the tip Chuck, wish I'd thought of it at the time, but it still came off without much trouble.
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 30, 2014, 02:17:11 PM
Very nicely done! :clap
Sent from my iPhone using Tapatalk

Thanks Mayor!  I really have enjoyed your ambitious work on your V65 too - a great photo essay.  It's going to look sweet!  ;-T


Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 30, 2014, 02:20:31 PM
Went through and made a few edits for clarity and more info.
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Chuck in Indiana on December 30, 2014, 03:25:45 PM
Went through and made a few edits for clarity and more info.

Most excellent, sir..  ;-T
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Guido Valvole on December 30, 2014, 04:20:39 PM
Thanks much! I sent my Monza rear drive to Sean Fader when sparkly bits came out with the oil. It needed all new bearings, the pinion-lube fix, and correct shimming. That last was a bit daunting… where a Guzzi is just like a bevelhead Duck. Sean's done that a few times… I haven't. But the V50 needs the fix as preventative maintenance so great to have this reference.
cr
Title: Re: Rear bevel drive seal replacement (small block)
Post by: sign216 on December 31, 2014, 07:05:14 AM
SED,
 great work! A valuable reference for the Guzzi community.   
Joe
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Antietam Classic Cycle on December 31, 2014, 09:41:26 AM
Why wouldn't you replace the small seal at the same time?
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 31, 2014, 12:24:32 PM
Why wouldn't you replace the small seal at the same time?

Well, next time I would! 

Other answers are that it wasn't leaking, I'm cheap and I didn't think about it!   :P
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 31, 2014, 12:33:33 PM
Why wouldn't you replace the small seal at the same time?

Charlie's right, next time I would replace both seals and the large ball bearing.  Maybe also the smaller roller bearing.

But this brings up a question - If the large ball bearing is changed do the the ring and pinion clearances need to be adjusted? (re-shimmed?)

I would think you could use the same shims because the bearings will have almost exactly the same dimensions.  (it is easier to make a bearing with very precise dimensions than a ring and pinion set.)

But does anyone know?
Thanks!
Shawn
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 31, 2014, 12:39:25 PM
Joe and CR - thanks for the compliments. 

Agreed - Sean Fader has a good reputation.  I considered sending this to him, but figured I could replace a seal.  Besides, I like learning new things!   :BEER:
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Chuck in Indiana on December 31, 2014, 02:41:15 PM
Sean is as good as it gets.  Replacing the big bearing would have no bearing  ;D on ring and pinion fit. It'll be as close to the same as you can measure.
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Guido Valvole on December 31, 2014, 07:49:47 PM
But that big bearing is $120 no matter where you get it. (cheap Guzzi content). Since there were bits of metal circulating through my Monza rear drive, all bearings and seals had to be replaced. ~ $300+ from a bearing supply house, all high-quality SKF, FAG, and such. No cheap Chinese junk. I *think* re-shimming is necessary only if the pinion bearings are replaced although shims H & I could be critical if they change the position of the crown gear relative to the pinion. The shimming procedure is covered in the shop manual. I thought about how much I'd save vs. how much it would cost if the rear drive failed at speed… and I'm as cheap as anyone.
cr
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on December 31, 2014, 11:26:18 PM
;-T
Title: Re: Rear bevel drive seal replacement (small block)
Post by: sib on January 01, 2015, 09:13:26 AM
No cheap Chinese junk.

Well, they did build the Great Wall, and it has lasted a while.  But, seriously, Chinese-made no longer equates with cheap or shoddy.  I'm old enough to remember when the same attitude was applied to items made in Japan, before they started selling Nikon, Toyota, and Sony products here and teaching us a few things about high-quality manufactured goods.
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Cassidy on January 17, 2015, 05:25:39 PM
SED,
Great discussion, too bad I discovered it after I performed the task. I am a new owner of a 78 V-50 and on the first 26 mile (rainy day) ride I came home with oil over the rear tire. Diving in, to replace the (3) paper gaskets which I thought were the culprits, I noticed the bolts on the ring gear seemed loose... no, one was sheered. The rest fell into place, if you're in that deep, might as well go for all the seals. You couldn't have described it better. Putting it all back together, I then found and read your piece and realized I missed the last seal and went back for a second operation. Still trying to get the (perhaps original) seal out, but I am there. (maybe not my oven yet, a girl's gotta cook).  One note I may add, after putting it back together the first time with new bolts and Loctite on the bevel gear. (it works). Breaking the Loctite is a cinch using Methyl alcohol (in my case, dry gas) A few drops and a mere minute does an amazing job.  Thanks for the pics too, they made me feel sane. Now if only the snow would leave.
Title: Re: Rear bevel drive seal replacement (small block)
Post by: kevdog3019 on January 17, 2015, 09:39:30 PM
Very nice; thanks for this.
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Muzz on January 17, 2015, 10:07:29 PM
Thanks for that, SED. Attaboy. ;-T We're beginning to get some small block stuff documented here. I wish someone would do the transmission..

That has been done.

Nick Webb documented this on "This Old Tractor". NolaGuzzi, Nick and myself all had gearbox problems. Theirs were to do with the pre-select fork, mine was somewhat more complex and required a lot more parts to fix. ::)

Written I might add with a humorous vein running through it!
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Muzz on January 17, 2015, 10:08:23 PM
I must say, great write up SED. ;-T
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Simmoto on September 18, 2018, 03:26:24 PM
This is a fantastic thread, I'm following the steps to replace the big seal on my Lario bevel drive. thanks!  :thumb:

Can anyone tell me how to replace the small, outer seal and the pinion seal while I'm in here? Promise to post up photos when I'm done!

Thanks  :grin:
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Chuck in Indiana on September 18, 2018, 04:33:21 PM
This is a fantastic thread, I'm following the steps to replace the big seal on my Lario bevel drive. thanks!  :thumb:

Can anyone tell me how to replace the small, outer seal and the pinion seal while I'm in here? Promise to post up photos when I'm done!

Thanks  :grin:

While you're there..  :grin: There is a mod to drill a hole so the pinion bearings get lubed. I posted something on that several years ago.. I'll see if I can find it.

It's in the Monza annual inspection thread:
http://wildguzzi.com/forum/index.php?topic=89034.60
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Simmoto on September 19, 2018, 12:59:43 PM
Thanks Chuck, yeah I'd read about that - it's beyond my ability right now so I'll leave it. Still trying to figure out the outer small and pivot seal removal.... :weiner:
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Chuck in Indiana on September 19, 2018, 02:02:48 PM
I've not done that one, so can't say. Shirley  :smiley: it can be done by ordinary mortals..
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on September 19, 2018, 11:33:51 PM
Thanks Chuck, yeah I'd read about that - it's beyond my ability right now so I'll leave it. Still trying to figure out the outer small and pivot seal removal.... :weiner:

Glad you are finding this thread useful - great! 

Don't be afraid to try drilling the oil passage.  It's easy to do now if you got the rear drive this far apart.  It's easy to start in the right place and the hole just has to end up close to the forward bearing.  Drill the hole, and chamfer & cut the burrs off with an exacto knife.

Start here:

(https://thumb.ibb.co/krcanK/IMG_2789.jpg) (https://ibb.co/krcanK)


Aim for here:

(https://thumb.ibb.co/nhoLMe/IMG_2791.jpg) (https://ibb.co/nhoLMe)
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Simmoto on September 26, 2018, 01:54:14 PM
So here's how I did the small seal. It's under a bearing that's pressed into the casing and you have to remove the bearing and the washer beneath to remove the seal.

The only way I could remove it was with a blind bearing extractor. Still a bit tricky as there's not much room between the bearing washer and the seal to get the lip of the extractor. In this case the seal was well and truly knackered.

Measure how much of the bearing is proud of the casting so you know how far to put it back


(https://thumb.ibb.co/bszZwp/1.jpg) (https://ibb.co/bszZwp)


Insert the correct sized puller beneath the washer that sits beneath the bearing


(https://thumb.ibb.co/dnpOp9/2.jpg) (https://ibb.co/dnpOp9)


Extract the bearing,


(https://thumb.ibb.co/cJfrbp/3.jpg) (https://ibb.co/cJfrbp)


Clean the housing. I found the old seal hard to extract so used the puller on that too.  Then push in the new seal - I used the face of the bearing extractor to tap it in. Then insert the washer and tap the bearing home so it's the same distance proud as it was before.


(https://thumb.ibb.co/bMe1bp/4.jpg) (https://ibb.co/bMe1bp)


Hope it's useful
Cheers


Title: Re: Rear bevel drive seal replacement (small block)
Post by: Chuck in Indiana on September 26, 2018, 07:47:55 PM
Yessir.. :thumb: I *assumed* it would be similar. Thanks for that.. :thumb: It'll be good when someone finds this in a search.
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on September 26, 2018, 10:07:04 PM
Yes - a great help.  It will give me courage when I have to do it.  Thanks!
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Diploman on September 28, 2018, 10:08:27 PM
This is an excellent, very helpful thread which will facilitate an operation that sooner or later will face most smallblock owners.  It's good that the photo doc is now complemented by a further, more recent bit on extracting the outer roller bearing and replacing the smaller outer seal.  All the possible upgrade operations are now covered:  large inner seal; large inner ball bearing; outer roller bearing; outer small seal; lubrication passage for pinion bearings.

When I replaced the large inner seal on my 1980 V50II in 2016, the outer roller bearing did not come out of its housing with the hollow shaft, as shown in the photo tutorial here.  I elected not to replace the small seal or the outer bearing at that point, since both were operating properly (and have continued to do so to date).  I extracted the hollow shaft from the large inner ball bearing with a shop press, but SED's whacking-on-wood method is more resourceful and requires less equipment.  Good show!

I can't remember where, but I read somewhere that a European smallblock owner who often rode his bike in the rain was frustrated at the need to repeatedly replace the large outer seal, due to corrosion which inevitably formed on the exposed steel edge of the hollow shaft outside of the seal, then degrading the seal. This, of course, is particularly a problem when the hollow shaft is often exposed to rain. 

The solution: a very thin stainless sleeve placed over the entire surface of the hollow shaft contacted by the seal.  This sleeve covers the edge which corrodes if exposed, preventing the surface from any further corrosion which will damage the seal.  Timken and SKF offer such sleeves, and probably other bearing manufacturers as well. The next time I replace the large seal I plan to install such a sleeve, which offers the promise of much longer life for the large seal, and far less hassle for the smallblock owner.

https://www.timken.com/products/timken-mechanical-power-transmission-products/seals/redi-sleeves/

http://www.skf.com/us/knowledge-centre/media-library/index.html#tcm:12-128020
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Diploman on September 29, 2018, 08:24:28 AM
A couple of notes:

- In his Guzziology discussion of the pinion-lube fix, Dave Richardson advises reversing the metal shim between the backplate gaskets so that it forms a sort of dam that makes lube pool above the upper side of the pinion bearing housing, thus allowing the lube to be driven down the (newly created) passage into the space between the pinion bearings.  Makes sense.

- Dave also discusses the inadequacy of the OE lock plates to secure the ring gear bolts. His solution, which he says works reliably, is simply to tighten the bolts -using red Locktite - directly down onto the ring gear, with no washers or other devices.  In recent years it seems to have become customary to use Schnoor washers for this purpose.  I followed the Guzziology recommendation when replacing my V50II big seal and have had no issues in over 8K miles.

-Recently a forum member started a thread on a new type of lock washer, the Nord-Lock. This, to me, sounds like an even better bolt-securing device than the Schnoor.  When/if I need to replace the big seal again, I intend to use the Nord-Locks.  (I already have a set of them on hand.)

https://www.indconsupply.com/nord-lock-3-4-locking-washer-carbon-steel-2150.php?gclid=EAIaIQobChMIw-jC36f42AIVXDkMCh1_dQBJEAEYAiAAEgKeYPD_BwE#yt_tab_products1
Title: Re: Rear bevel drive seal replacement (small block)
Post by: SED on October 04, 2018, 11:21:35 PM
Great addition Diploman - thanks!
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Simmoto on October 05, 2018, 06:14:00 AM
Yeah some really good contributions from Diploman! I agree completely with the corrosion on the  hollow shaft causing the big, inner seal to leak. SED says in his thread he had this issue and so did I - we both used 400 grit to remove the rust but a stainless band would be a better solution I would think.

My rear disc is now hot after a ride - I can touch it but I wouldn't hold it for long! I am pretty sure its heat conducted from the bevel drive as there's no binding of the rear pads. The housing is cooler on the outside and around the pinion so I don't suspect the cogs. So it's either paranoia on my part (after all its probably always been hot and I didn't notice) or something to do with the big inner ball race bearing - that I didn't touch. of course I never touched the rear disc before the bevel rebuild so no baseline.....Can someone confirm it's paranoia -  :cheesy:
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Chuck in Indiana on October 05, 2018, 07:42:01 AM
Weird. I went back to some small block threads where I documented reversing the metal shim, Nord Lock washers, etc. and the pictures are *gone.* The last time I looked, Photoblockit had released their hold on them, and they showed up. Even Flickr pix are missing? What up with that? <Grumbling and shufflin off>
Title: Re: Rear bevel drive seal replacement (small block)
Post by: Simmoto on October 05, 2018, 11:46:14 AM
Yup that's odd Chuck....no images?

I've added 10ml of moly, and will see if that reduces the friction/heat generated. I just added the end of an old tube when I filled it up so very little in - forgot...