'04 EV Touring Foot Pedal, No Brakes Issue. Solved!!

[Tom H]

I need some help to confirm what I have found to be the issue with my foot brake pedal. I MAY have a bad master cylinder?

A bit of history: I did install 1" lower shocks in the rear without adjusting the foot brake bias? valve. So rear pad could wear more than fronts. Bike has about 25,000 miles or less on it, might be more like 20,000?

I may have noticed this coming on a few days earlier? Freeway ride home and went to hit the brakes to get off the freeway, hand brake was fine, but the foot pedal was VERY soft and just about to the floor board. Quick visual inspection at a traffic light showed no leaks on the tires. Another field inspection when I was off the bike again showed no leaks. Wanted to make sure I was not going to slip on a tire covered with brake fluid.

Garage inspection with more light. No leaks as far as I can see. No leaks from lines, calipers or master cylinder. Brake pads looked MAYBE a little low, rear brake the lowest. Master cylinder reservoir is half full. Pump the pedal and it does not gain height, as in if there was air in the lines. Note: when I have had leak issues with my '62 Ford F100 manual brakes, I could pump the brakes quickly to get pressure up.

To try so solve the issue, I removed and inspected the LH front and rear pads. Rear pad was about 2mm thick for the friction mat'l, front was 3mm. New S/B I think 4mm. I changed the rear pads with new EBC HH and re-installed the front LH pads. No change in the pedal. Thought it may have been due to worn pads. BTW: RH front was about 3mm as well, so only the rear was really worn.

My shock change may be leading to more rear brake wear. The manual says not to mess with shock length or brake issues could happen. I MAY adjust the bias adjuster to take out some rear brake. There is a measurement for the adjuster, might have to set it to that.

So with all this info, the pads are fine. The pedal is soft and will not pump up, as in air in the line. I think my master cylinder has bit the dust????? What would you think????.....

So I was looking for rebuild kits or a new M/C. For the kits as listed on fleabay, not sure what kit to get? M/C S/B listed as 15-16mm per MG Cycle, couldn't find a kit at MG??? Fleabay listed a few kit's at about $29. A NEW M/C was listed at about $85 that I'm sure will fit. What kit do I need to get? What is the Brembo number for the kit that I MAY need?? Many kits listed on fleabay list the Brembo number.

So, do you think the M/C has bit the dust, or am I looking in the wrong direction? The linked brake thing may be throwing me off??

If the M/C has bit it. Again, what kit do I need or is it better to just buy new?

Thank you for the time to read this and hopefully a solution!!
Tom

[Chuck in Indiana]

So with all this info, the pads are fine. The pedal is soft and will not pump up, as in air in the line. I think my master cylinder has bit the dust????? What would you think????.....

So have you tried bleeding the system to see if the m/c *can* pump?

[Sasquatch Jim]

 Years ago they bled people to stop whatever ailed them. 
 Bleeding your brakes may make them stop.

[Wayne Orwig]

This is not likely to be it, but you should check.
A failing wheel bearing can let the wheel wobble. That will push back the brake pads. So the brake will be soft. Verify that the wheel bearings are tight while looking at things.

[Chuck in Indiana]

This is not likely to be it, but you should check.
A failing wheel bearing can let the wheel wobble. That will push back the brake pads. So the brake will be soft. Verify that the wheel bearings are tight while looking at things.

Yeah but..  Normally you can pump the brakes back up in that scenario.

[pehayes]

I had this same problem with a 98EV although much higher mileage.  Internal rubber failures in the M/C and won't show as an external leak.  If you can get any pressure on the pedal, put a brick on it and see how long it takes to bleed down to an end stop.  Rubber part failures are more likely with age than with mileage and yours is no spring chicken.  There are NO rebuild kits.  Lawyers got in the way.  I purchased a replacement M/C from YoyoDyne and has performed fine ever since.  This is the notation from my service file:  "Rear master cylinder.  Yoyodyne. SKU 10.4776.65 also MGCYCLE or Harpers 31666990".  I can't find it on Yoyodyne any longer but a Google search for the part number found this:  https://www.tawperformance.com/brembo-rear-master-cylinder12246372  Not sure if your 2004 uses the same part as my 1998, but likely so.  Also here: https://store.bevelheaven.com/Brake-Related-Parts/Master-Cylinder-Brembo-Rear-Brake-16mm-Lever-Type-Black/

Also, regarding the brake proportioning valve, I used shorter shocks to lower Regina's 98EV.  I studied the factory bulletin on the pre-set measurement and simply fabricated another adjuster bolt.  I wrote it up here:  http://www.guzzipower.com/IntegEVBrakes-Pat_H.html

Patrick Hayes
Fremont CA

[Orange Guzzi]

Brake lines can fail internally.  Check to see if fluid is passing through to the front brake.  Line could be plugged somewhere.  Can cause the brake caliper not to retract also. 

[Sasquatch Jim]

Make sure the horn works loudly.

[Tom H]

The pedal just about hits the floor board, but there is still just enough brake left to slow the bike, just not confidently stop it. There is enough pressure to work the brake light switch.

When I tried to pump up the pressure, it did not seem to do any good. But, I'll give bleeding them a shot and see if somehow air did get in the lines.

Thanks for the link on the M/C's. Seems about $85 is the going price. There are kits on fleabay, but none listed this M/C as far as I could tell.

FYI: there is a place in England that is selling the seal kits for the Brembo Gold calipers. Just no pucks listed.

Thanks for the help!!!
Tom

[Kiwi Dave]

If you haven't already, replace those worn pads.  I realize that they still have some meat left on them, but this action cured a similar issue I had with an EV Touring.

Bleeding linked brakes can be a pain in the butt.  I found reverse bleeding to be the most successful, but you will need a helper.

[geoff in almonte]

You mentioned in your original post that the rear M/C was only half full.

Did you try adding some brake fluid?

Dumb Q, I know, but sometimes......

Good Luck!

G

[Tom H]

On the NEW EBC HH pads, the friction mat'l is right at 4mm. Both the LH and RH front was right about 3mm, maybe a tad thicker. The rear was about 2mm and I did change it out to a new set. No difference. Good thought though, it was what I was thinking when I checked on the pads before anything else. On disc brakes it shouldn't matter, drum it make a difference.

The M/C only half full, it is between the min and max marks. I was concerned that with possibly badly worn pads I may have run out of fluid and let air into the lines.

Thanks again!
Tom

[Sheepdog]

The foot brake on my Vintage developed similar symptoms. When I brought it to the Guzzi dealership for service, the techs were able to correct it by flushing and adjusting the master cylinder. I had always been disappointed with the Advanced Brake Pedal that I installed until the Guzzi techs made it function as intended. Now it works better than ever. I’m sorry that I cannot provide any more details, but the problem was correctable in my case...

[Tom H]

Well, my brake issue "may" be solved.

I replaced the master cylinder and bled the brakes, Tonight all seems well. I will check again in the morning to see if I still have a firm pedal.

Changing the master was straightforward. Bleeding was an issue.

My vacuum bleeder did not work as usual except for testing the master, POS.

I was doing the work by myself. I did buy a set of Speed Bleeders. They do "seem" to work and do as described so far. Seem?? Only because I think it "may" have been better to do a traditional 2 person bleed job. Took quite a while to get the air out of the lines.

Interesting note on the linked brakes:

While bleeding, I went to the front first since it's the longer line. The longer line is normally where you start first. Well...... I got the air out as best as I could and checked the pedal, firming up. Then moved to the rear. Got the air out of there and checked the brake pedal. No brakes. What????!!!

So I went back to the front and bleed again. Took quite a while to get fluid to come out. Bunch of air in the fluid once it started coming. Checked pedal, almost firm.

Bled rear again and solid fluid came out after two pedal pumps. Checked front again and with 2 pedal pumps solid fluid again. Pedal "I think" feels like it did before the cylinder failed.

The bleeding description is a bit of a condensed version. I did have to repeat the bleed a few times while taking notes on what happened each time.

Best as I can tell, if you bleed the rear/short line first, then the front, all seems to go smoother. Also, the front line has a pressure regulator in the line, not just the proportioning valve. Maybe this is why it's tough to bleed the brakes.

As a note: When I tried to leave both front and rear Speed Bleeders open to solve the air issue in the front when I bled the rear. When I pumped the pedal, only the rear had fluid come out, nothing from the front. When I closed the rear, fluid came out the front. I think this is due to the regulator built into the front line?

This was not fun, but was a learning experience! I will find out tomorrow if I have fixed the brakes or not. I hope so!

Thanks Chuck for the tip, couldn't find a meat injector local. Already had the Speed Bleeders on the way.

Thanks again for the help!
Tom

[Tom H]

Took the bike for a spin. All went well. The pedal so far feels like it should.

It appears that the rear master cylinder did fail.

Again, thanks for the thoughts!
Tom

[Huzo]

Just for my information.
If the rear master is not leaking, and the piston within is moving, what failed within the replaced m/c to cause the issue ?
Was the piston in the master binding and not retracting far enough to allow the priming hole to connect to the fluid reservoir ?

[Tom H]

The original MC would pull fluid from the resivor, just would not get pressure to make the brakes work right. Why...I don;t know.

Tom

[Huzo]

The original MC would pull fluid from the resivor, just would not get pressure to make the brakes work right. Why...I don;t know.

Tom

Ok that narrows down the possibilities but anyway you've solved he issue.
Would be good to look into the old one though.

[Tom H]

I plan to tear it apart and see if I can figure out the problem. I read up on how to take them apart, but there was no mention or a rebuild kit part number.

There is a rebuild kit on fleabay that "may" work for this MC, but the add does not specify this MC. Maybe I can find more info about it's dimensions and see if it will properly fit my MC.

Tom

[Chuck in Indiana]

Attaboy, Tom.  Knowing you *can* do it is half the battle..

[pehayes]

Just for my information.
If the rear master is not leaking, and the piston within is moving, what failed within the replaced m/c to cause the issue ?
Was the piston in the master binding and not retracting far enough to allow the priming hole to connect to the fluid reservoir ?

I had the same failure.  IIRC, the piston has multiple seals on it.  The final outboard seal keeps reservoir fluid from leaking outward past the piston to drip.  It only experiences gravity pressure from an inch or so of fluid head.  Even a bad seal will hold that.  The inboard seals are the ones that generate pedal pressure.  The slightest nick, tear, wear in that seal will bleed off pressure quite quickly.  The piston moves, but fluid in front of it moves past the seal and back behind it.  No pressure, no dripping.  That's what he has.

BTW, when bleeding.  It helps to remove each caliper, place a wooden block between the brake pads, twist and raise the caliper so that it and especially its bleeder valve becomes the highest possible point for bubbles to rise and escape.  Otherwise, keep the caliper as low as possible and use a syringe to bleed backwards toward the reservoir.   Have an accomplice so you don't spray out of the reservoir and don't overfill the reservoir with back flush.  Use a little suction tool to suck the flushed, dirty fluid out of the reservoir.

Patrick Hayes
Fremont CA

[Huzo]

Rebuilding the old one will mean you have a spare, but when are you going to use it ?
Gaining the knowledge of what went wrong is the valuable commodity.

[Huzo]

Good one pehayes.
Didn't know that, but will be the better for it if I ever have to go in for a look.

[Tom H]

Thanks Patrick!! No leaks that I could find. Just a loss of pedal pressure that you could not just pump the pedal to get pressure back like you can do with car drum brakes out of adjustment or a little air in a disc brake system. And you reminded me...

I did pull the rear caliper to get the bleeder screw pointed up. I also "tried" to removed the proportioning valve while the brake lines were connected, couldn't get it out. But I did manage to get it so that the brake lines were more or less up rather than on the side.

I also used an item to keep the pads wedged open on the rear caliper. The front I left mounted since it's bleeder was facing up. I also used a soft hammer to "tap" on the calipers, MC, distributing block, and proportioning valve to try to break up any air bubbles and get them out. And I did state tap, not beat with the hammer.

Thank you all again!!!
Tom

[twhitaker]

If all the bleeding was while on the centerstand maybe the bias valve came into play.