Page 1 of 2

Brakes Sticking

Posted: Sat May 13, 2017 4:41 pm
by Darbronnoco
I woke the beast up from its winter slumber and on my test drive I noticed that my brakess seemed to be dragging a bit. The brakes would stay somewhat engaged after applying and feel a bit soft at that point. I could lift up the pedal with my toe and it would stop dragging. If I give the brakes a few pumps it feels like I have good pressure. My thought is that it could be a semi blocked compensating port. I don't see any obvious leaks and break fluid level looks fine. Everything was fine before storing this winter in my garage. Hoping for some ideas and things to check from the wise sages/asses here. Thanks!

1974 type 2.

Re: Brakes Sticking

Posted: Mon May 15, 2017 7:47 pm
by Amskeptic
Darbronnoco wrote:
Sat May 13, 2017 4:41 pm
I woke the beast up from its winter slumber and on my test drive I noticed that my brakes seemed to be dragging a bit. The brakes would stay somewhat engaged after applying and feel a bit soft at that point. I could lift up the pedal with my toe and it would stop dragging. If I give the brakes a few pumps it feels like I have good pressure. My thought is that it could be a semi blocked compensating port. I don't see any obvious leaks and break fluid level looks fine. Everything was fine before storing this winter in my garage. Hoping for some ideas and things to check from the wise sages/asses here. Thanks!

1974 type 2.

Is the brake pedal lever sticking due to rust? Pull belly pan and pull down on the lever that the pedal bolts to. If it is difficult to pull and stays down even, you need to free up the pivot with penetrating oil followed by as thorough a lubrication as you can muster.
Is your booster not releasing?
Any dampness at the wheels?
Colin

Re: Brakes Sticking

Posted: Tue May 16, 2017 12:52 pm
by sgkent
I concur that either the position of the pedal, due to rust, stiff grease, weak or broken pedal return spring, booster, or master is causing, as you put it "semi blocked compensating port." The other possibilities are swollen brake lines, or delaminated brake lines that allow fluid to flow easier to the brakes than return.

Re: Brakes Sticking

Posted: Tue May 16, 2017 6:49 pm
by kreemoweet
It's most likely a booster or pedal linkage issue. There are about 6 springs in the various mechanisms involved all tending to return
the brake pedal to it's fully undepressed position. It should rise fully and rest against the rubber stop pad on the underside of the
cab floor. When so situated, there should be no pressure between the pedal linkage and the booster actuating rod. It's an easy thing
to check.

Re: Brakes Sticking

Posted: Thu May 18, 2017 4:16 am
by Darbronnoco
Thanks for the feedback. Hopefully I can get a break (no pun intended) from this thphoon weather so I can get a better look.

Thanks

Re: Brakes Sticking

Posted: Tue Jun 13, 2017 6:37 pm
by Darbronnoco
ok only a bit of rust and oil in my eyes. I noticed the the brake pedal isn't resting on the rubber pad on the base of the cab. I can pull down on the pedal and its a bit slow to return. When I pull down the pedal it wounds a bit light a squish sound if that makes any sense. How can I check the booster? Any way to do that will it's still on the bus?

Re: Brakes Sticking

Posted: Tue Jun 13, 2017 7:19 pm
by Darbronnoco
Do I need to adjust the rod to make the brake rest on the rubber pad?

Re: Brakes Sticking

Posted: Tue Jun 13, 2017 9:31 pm
by Darbronnoco
kreemoweet wrote:
Tue May 16, 2017 6:49 pm
It's most likely a booster or pedal linkage issue. There are about 6 springs in the various mechanisms involved all tending to return
the brake pedal to it's fully undepressed position. It should rise fully and rest against the rubber stop pad on the underside of the
cab floor. When so situated, there should be no pressure between the pedal linkage and the booster actuating rod. It's an easy thing
to check.

I only see the one main return spring. Where are the others I should be looking for? The Bentley photos are not super detailed here. I'll double check tomorrow but I don't recall there being any tension on the clevis pin. Thanks for your response.

Re: Brakes Sticking

Posted: Tue Jun 13, 2017 9:36 pm
by kreemoweet
The other springs are internal to the master cylinder and booster. No need to be looking for anything, the point was that a sluggish-to-return
brake pedal is a very abnormal thing. Typically the brake pedal will briskly slam against the cab floor when released.

Re: Brakes Sticking

Posted: Tue Jun 13, 2017 9:40 pm
by Darbronnoco
Is the large spring have the most say in said pedal return? I'll have to give it another basting of PB and maybe a bit of gentile agitation with my mallet to make sure it is free of rust and crud. I can try and add a video of the pedal action if that would be beneficial.

Re: Brakes Sticking

Posted: Tue Jun 13, 2017 9:42 pm
by Darbronnoco
I'm also a bit skyeptical of what are probably the vaccuum lines. They don't have a clamp of any type and seem like they could be loose. How much impact on pedal return could leaking vaccuum have if any?

Re: Brakes Sticking

Posted: Wed Jun 14, 2017 8:15 pm
by Darbronnoco
Well after lots of lub and some tapping (I'll leave the jokes to you guys) the breaks seems to be behaving much better. I think I'll have to get on the schedule for next year Colin! The master calendar looks pretty darn rusty and probably looking for some love.

Re: Brakes Sticking

Posted: Thu Jun 15, 2017 5:56 am
by sped372
kreemoweet wrote:
Tue Jun 13, 2017 9:36 pm
Typically the brake pedal will briskly slam against the cab floor when released.
Agreed. Hope you got it cleared up!

Re: Brakes Sticking

Posted: Thu Jun 15, 2017 7:49 am
by Darbronnoco
It still doesn't slam up and there is about a fingers width distance between the rubber stop and the leaver. The return is much better than before. could the spring be weak?

Re: Brakes Sticking

Posted: Thu Jun 15, 2017 8:09 pm
by kreemoweet
Darbronnoco wrote:
Thu Jun 15, 2017 7:49 am
It still doesn't slam up and there is about a fingers width distance between the rubber stop and the leaver. The return is much better than before. could the spring be weak?
Certainly, the spring could be weak. Or something's wacky with the rest of the brake pedal linkage parts. Or someone installed a huge
cast-iron brake pedal. Or the servo is putting some sort of hold on the pedal. The last can easily be checked for by disconnecting the
clevis pin and seeing if the pedal acts any differently.