Wildguzzi.com
General Category => General Discussion => Topic started by: twodogs on June 14, 2022, 07:01:03 AM
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OK I am losing brake fluid out the rear mc, I believe that it is coming out the plunger up front, I don't really know if I can rebuild it or replace it. I see that MG cycle has a rebuild kit for a 15mm mc but I'm not sure if that is what I have. The bike is the 77 convert, would it be better to try and rebuild it or try to find the whole mc? I'm okay either way but the whole mc is pricey, as always thanks for any help.
Bruce
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Without disassembling your M/cylinder and inspecting the bore, it's impossible to say whether a kit will fix it.
Especially on a 45-year-old M/cylinder.
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If the bore on the Master Cylinder isn't scored or pitted, it can usually be rebuilt.
If the Master Cylinder IS scored or pitted, there's a company that will
sleeve the old one with stainless steel tubing - permanent repair that's
literally better than new.
Can I remember the name of the outfit? (Of course I can't! :grin: )
I'll look, though.
Update:
Here are a couple of companies you could contact:
https://www.applehydraulicsonline.com/collections/motorcycles
https://brakeandequipment.com/portfolio-view/sleeving-master-cylinders-wheel-cylinders-and-piston-calipers/
(Disclaimer: I've never used 'em, but they're an option.)
-Stretch
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I use a gun brush to clean the bore for inspection. Look in manual all of it is covered as long as you can read plus do what you read. It's up to your abilities. I think it's easy, I have one to do but no room between sidecar & Cal2. Just don't want to take it off right now. Not a bad job, just keep lots of real wet rags on hand.
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Thanks for the replies so far, I think I can rebuild if it is not scored, at least try, I was just hoping that someone could tell me what rebuild kit I need to order, I've seen one from MG cycle for a 11mm and a 15mm but their description to me is a little vague, I'm trying to get it up on the lift and at least check it out to make sure it is worth doing. I'll keep poking along and let you know how it goes.
Bruce
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Thanks for the replies so far, I think I can rebuild if it is not scored, at least try, I was just hoping that someone could tell me what rebuild kit I need to order, I've seen one from MG cycle for a 11mm and a 15mm but their description to me is a little vague, I'm trying to get it up on the lift and at least check it out to make sure it is worth doing. I'll keep poking along and let you know how it goes.
Bruce
This one: https://www.mgcycle.com/index.php?main_page=product_info&cPath=110_112&products_id=753
"Fits rear master cylinders on all integrated system disk brake big twin models from 1976 through 2010"
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Thanks Charlie, I was looking at that one, just needed a little clarification, got one coming, see how it goes from here :boozing:
Bruce
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Thanks Charlie, I was looking at that one, just needed a little clarification, got one coming, see how it goes from here :boozing:
Bruce
Simple enough to install. If you need any help, just give a shout.
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Roger that :bike-037:
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If the bore on the Master Cylinder isn't scored or pitted, it can usually be rebuilt.
If the Master Cylinder IS scored or pitted, there's a company that will
sleeve the old one with stainless steel tubing - permanent repair that's
literally better than new.
Here are a couple of companies you could contact:
https://www.applehydraulicsonline.com/collections/motorcycles
https://brakeandequipment.com/portfolio-view/sleeving-master-cylinders-wheel-cylinders-and-piston-calipers/
(Disclaimer: I've never used 'em, but they're an option.)
-Stretch
Hey Stretch, thanks for the info!
Speaking of leaks.......the trapezoidal reservoir front brake mc on my '87 LMIV is leaking again. I replaced the piston seals & diaphragm in 2010 and have perfromed fluid changes every 2-3 years since. When I bought the Pump Cover Kit (28661100) & Pump Gasket Kit (28659300) from Moto International I had requested two of each but they told me that they only have one each and that they are probably the only ones left in existence. I've recently reached out to Brembo, Stein Deinse & Gutsibits but thy're indicating NLA so I guess I'll reach out to your sources to possibly see what other options I have. Or do I scrap the whole rh throttle tube, switch gear & brake mc assembly??? And, what do I replace all that with?? Damn, I just thought all I had to do on the LMIV this season was install the new tires I recently bought, oh well.
Art
PS - Suggestions, recommendations & comments are welcomed. I can't ride this bike until this brake issue is resolved. Thanks!
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Hey guzziart, there have been some great ideas from this group that have kept me riding on my guzzi, I'm no wrench but with their help I'm willing to try, with that being said you might want to start your own thread so they can help you, they might miss your question here :boozing:
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Yeah, good point TD. This trap mc subject came up in another thread here about a year ago but there was less info on available resources then. Not only does my LMIV need help but an aquaintance on the V11 Lemans Owners board also has an LMIV with the same frt brake mc leak issue so I know that at least two of us are looking for some resolution/options.
Art
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I feel your pain Art, I wish I could help you. I have a rebuild kit that should show up today that I'm going to give it my best to rebuild, a little nervous but more nervous about bleeding the linked system after I put it back together, I have read some good info on the subject, so will see how it goes. GL with your search.
Bruce
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OK I got my rebuild kit and I'm working on taking the mc off but I'm not sure of something, I have the banjo off and the Allen bolt out and the 2 nuts off and the brake rod off and it won't move, is there anything inside the battery compartment that needs to be taken off?
Bruce
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OK never mind my question, I took the battery out and found the nut and pulled it off 🙃
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OK I'm getting conflicting ways of reassembling, does the metal washer go in and then the stepped rubber washer with the locking ring or does the rubber washer first then the metal washer and locking ring?
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The one that looks sort of cupped goes on top of rubber to lock it in place. Should be a narrow part as wide as the rubber flat.
Edit--- went & looked at my kit, not in order. OK, looked in SP & G5 book.
Washer on bottom then rubber then lockring. Hit it hard.
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(https://i.ibb.co/4RgqDrh/15-mm-master-cylinder-assembly-order.jpg) (https://ibb.co/4RgqDrh)
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OK I have it assembled right and I can't get the socket in far enough to get the locking ring in to the grove, my socket stops just short, how do you hold it in to whack it? Plus I don't have no books that show anything.
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OK I don't have a long 12 point only a 6 point and I can't get it to lock in the ring, I can push the seal into it by hand but not far enough to lock.
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I use a deepwell socket and in the center a long nail or pin to push in piston.
On one hand use 2 fingers to hold socket or 3rd finger & thumb and 1st finger to push nail & piston in, then hit it hard.
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Borrow deep socket at the Auto store or buy at Pawn shop!!
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This is what I took out, not even close plus there was no locking ring, probably why it was leaking.
(https://i.ibb.co/K6hHcM5/16554956270107913313651593649797.jpg) (https://ibb.co/K6hHcM5)
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OK I have it assembled right and I can't get the socket in far enough to get the locking ring in to the grove, my socket stops just short, how do you hold it in to whack it? Plus I don't have no books that show anything.
There is a step in the bore, make sure the socket you're using just fits into the bore the seals slide in. I had to grind down a 9/16" socket to work.
I don't "whack" it - I prefer to use a large bench vise as a press to push it into place.
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Well all this time I had the snap washer in backwards and I finally got it turned around, which I thought I had tried, so after I turned it, it went right in, jezz :violent1: tomorrow I'll try bleeding the system. Thank you guys for all the help. Thanks again for your patience :boozing:
Bruce
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Well crap, so I buttoned up the mc with the wife's second set of eyes and showed her a video and let her read the instructions and we put the snap ring in and it worked, so today I had her help me bleed the brakes and one of the two bleeders on the front caliper snapped off, doh, no problem we got the other one to break free and then bled the front and then the rear and had brakes, so I took it outside and washed it all off and put it back on the lift to recheck everything and noticed the rubber washer near the brake arm,what the hell? How did it get past the snap ring? OK so I was checking the pedal and noticed it was leaking out of the mc, turns out the mc cap was leaking, so I put the old cap back on and the leak stopped. Some days I should have just stayed in bed :boozing:
Bruce
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OK I know I had the inside of the big part of the rubber washer up against the steel washer inside with the smaller part of the washer inside of the snap ring, the snap ring is still in place, any idea of what I did wrong? The wife even watched me install it that way. Thanks for any help.
Bruce
(https://i.ibb.co/TwTvV8b/20220620-092942.jpg) (https://ibb.co/TwTvV8b)
upload pic (https://imgbb.com/)
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Looks like you didn't get lock ring in far enough to catch.
Again use a nail w/head on it to push in the piston as you slide socket down, push in piston far as you can.
Charlie puts his in a vise, you may want to try his method. Might be easier.
Not the easiest to push in piston down the center of socket & hit the edge of it to seat the lock ring.
They look to be assembled correctly, flat washer, rubber on top then lock ring.
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I use a 15mm deep Snap On socket to knock the ring into place while the m/c is held vertically in the vise. Works every time
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Thanks for the replies folks, I put it in like guzzisteve suggested with the wife's help, I tried the vise but couldn't get it to lock in for some reason. I'm going to leave it for now since I don't ride it in the rain and crap, not that it would hurt the old girl, I believe it is more or less a dust seal, I'll just keep pushing it back till I get another kit one day since I'm pretty sure what I'm doing now :boozing: