Rear Brake Lever Travel?

[MPittma100]

My 1981H Venturer has a bit of an issue when I apply the rear brake. It travels too far. I really have to pivot my foot a lot to get it to apply the brake well enough. It would skid the tire if you pushed it hard enough. So it is working.

The bike has 26K miles. Pads have plenty of lining on them and I suspect they are OEM - do not know for sure. It had even more travel when I first acquired it. At that time I checked the free travel adjustment (which was in spec.) and bled the brake. The fluid was very discolored. This did help some, but it has considerable more travel than my 79SF. The pedal will not build if you pump it.

The SF has EBC pads, but I do not know if that applies. I realize that the Venturer is heavier, but the travel is too much and causes me to really "put my foot down". Almost makes you want to use your heel? I have tried adjusting the lever at the master cylinder and that does bring the pedal up, but there is no more free travel.

Any suggestions are welcomed.

MP

[bikerphil]

You could move the pedal one spline so it is further up and readjust the plunger bolt to where it feels comfortable. There should be a witness mark on the pedal and the splined shaft for the proper position.

[MPittma100]

Pedal Height

You could move the pedal one spline so it is further up and readjust the plunger bolt to where it feels comfortable. There should be a witness mark on the pedal and the splined shaft for the proper position.

Would there be any difference if I adjusted the plunger bolt without reclocking the pedal? Clocking is correct now with witness mark. I am wondering about the necessity of keeping the .050" free travel.

MP

[jetmechmarty]

Did you do anything that could have introduced air into the system?

[TopCatGr58]

Hey Pitt,

What worries me about what you said is that it won't build up pressure with repeated pumps!? That sounds like AIR in the line, I would suggest rebleeding it, you should be able to get a FIRM pedal with a few pumps. The other thing could be that the caliper piston is not sliding outwards towards the rotor and staying there, but is fully retracting back into the caliper housing so you have to push a bunch more fluid into it before it moves far enough to again contact the rotor. Perhaps a binding piston seal or corrosion behind the seal pinching the piston...seal actually ROLLING inwards instead of allowing the piston to slide towards the rotor? JAT or two!

T.c.

[MPittma100]

Hey Pitt,

What worries me about what you said is that it won't build up pressure with repeated pumps!? That sounds like AIR in the line, I would suggest rebleeding it, you should be able to get a FIRM pedal with a few pumps. The other thing could be that the caliper piston is not sliding outwards towards the rotor and staying there, but is fully retracting back into the caliper housing so you have to push a bunch more fluid into it before it moves far enough to again contact the rotor. Perhaps a binding piston seal or corrosion behind the seal pinching the piston...seal actually ROLLING inwards instead of allowing the piston to slide towards the rotor? JAT or two!

T.c.

Yes, the caliper could not be staying like it should. I am guessing that there is a residual check valve in the master cylinder (like most systems have) to keep that piston from returning. However, if that was not working, the pedal should firm up after a second pump.

Letting air in the system is a possibility, but I do distinctly remember bleeding the old fluid out until the new started. At that point the pedal was better than before but not solid like the SF. The old fluid was very weird looking. It was a red wine color? I bled the front at the same time and the fluid was in the same condition, but front has a full pull to the lever.

I suppose that looking at the caliper is the next move after bleeding again. If it does need to be rebuilt, where would be the best place for a kit? Maybe the master cylinder should be rebuilt as well?

MP

[bikerphil]

Would there be any difference if I adjusted the plunger bolt without reclocking the pedal? Clocking is correct now with witness mark. I am wondering about the necessity of keeping the .050" free travel.

MP

I'd try reducing the free play some more but not so much to cause the caliper to drag, see what happens.

[Crusty Snippets]

Brake

What TopCat said.
I would remove the caliper and pump out the piston. Might take many many pumps. Clean everything with the piston seal removed. Put the proper grease on the seal, anti seize on the pucks / pads and bleed it again.
Sometimes it takes lots of pumps to get a solid pedal. Using a clear hose on the bleed screw lets you see the air bubbles, and later the lack of air bubbles.
Time wise it makes sense to me to take it apart.

Unkle Crusty

[SFerinTEXAS]

Have my rear m/c off the SF right now, the exact same symptoms. Found spooge hole clogged .Apparently it was still sorta working with just the fluid trapped in the m/c bore but would not pump up. doing a complete strip and clean tonight.

[MPittma100]

Clogged up master cylinder

Have my rear m/c off the SF right now, the exact same symptoms. Found spooge hole clogged .Apparently it was still sorta working with just the fluid trapped in the m/c bore but would not pump up. doing a complete strip and clean tonight.

I have not had one of these apart. Is this spooge hole easy enough to see? Are you going to install a rebuild kit or clean only?

MP

[SFerinTEXAS]

I have a rebuild kit bought long ago. Intend to have it for a while longer.Lots of peeps here will advise a good cleaning(disassemble) generally cures brake issues as do I. You will be surprised at the crap build up in this stuff.

Not saying this is Your problem,just certain its mine. Search "spooge hole" on this site and look for the ones pertaining to the rear m/c. A complete tear down and cleaning of all the brake system parts is fair advice.

[jetmechmarty]

[MPittma100]

Update

Removed and disassembled m/c. Noticed adjuster push rod was quite rusty and found that m/c plunger seal was leaking. M/C was almost empty. Inside was not all that dirty. Also the reservoir o-ring was broken. Have a kit on the way, will install and see if that cures problem. The bore of the m/c needs a little attention. Any suggestions on how to clean that up?

MP

[bikerphil]

Looks like you found the problem. To clean out the bore, I have used a wooden dowel a little smaller than the bore. I cut a slot down the middle lengthwise a few inches and slip in some 320-600 grit paper and wrap around the dowel, then twist it in the bore. Rolled up sandpaper alone without the dowel will also work.

[MPittma100]

Finally

Got the m/c and caliper kits today. Noticed that m/c kit does not include the reservoir o-ring. Now I wonder why that does not come in the kit? I mean it is part of the m/c and of course the old one is split. Oh well.

MP