Rear brakes grabbing

[Dadevilledisco]

This is on a series IIA 88 10 inch right rear. I have bled the brakes.

Installed new brake cylinder and the trailing shoe is rubbing on the drum causing severe intense heating. The cylinder pushes out the trailing shoe. The lead shoe is where it should be and the cylinder piston is recessed as it shoulder be. What is could cause this cylinder to push out the top part of the trailing shoe? Cannot spin the wheel when raised off the ground. Snail cam is adjusted all the way in as these are brand new shoes but the lead shoe is not the problem. All springs are correct as far as I can tell.

Do I have a bad wheel cylinder. I have attached photos to show how the trailing shoe is being pushed out by the wheel cylinder.

[Dadevilledisco]

Changed lower brake springs to check if the Left held stronger than the right and same problem ensued. Do I have a bad wheel cylinder or too much pressure on the RR brakes causing the trailing shoe to engage the drum all the time?

I did just install new ss rear flexline but dont see how that should be a problem. We bled them yesterday without any problems.

Any Ideas?

Mark

[artpeck]

For what it is worth I had the same issue on my 73 88" rear brake. Had a POS new cheap cylinder fail so replaced it with an OEM part and replaced the old shoes at the same time. Bleed adjusted etc according to spec and it was sticking. Springs all good. Installation correct. It smoke after driving it very far. My conclusion ultimately was that the shoes were slightly too thick and it corrected after they modestly wore in. Sounds crazy but now it is fine without fixing anything.

[Dadevilledisco]

Art,

I went less than a mile for a test driving and hot does not even begin to describe what they were! Couldn't touch the wheel, drum or lugnuts with bare hands! Awful smell as well. i feel like this is the wheel cylinder as it is sticking out further than the lead shoe side.

Thanks for the input.

Mark

[jac04]

From the pics, the trailing shoe piston is definitely not going back in far enough. Can you push it in any more by hand? If not, it's a faulty cylinder. If so, then it may be a weak/improper return spring.

[artpeck]

Got it. Mine were for sure not that bad. I would agree that either the spring is bad (or miscounted which is easy to do) or the cylinder had gone bad on you.

[Dadevilledisco]

I switched springs with the LR and it still was pushed out too far. Yes I can push the piston in all the way but it returns immediately where as the LR is very slow about extending out with the drum off. I rebuilt the LR myself and bought a new one for the RR which is not acting right. Going to call RN this am and discuss.

Thanks

Mark

[xsbowes]

FWIT-BritPac has springs for 88 @ $.49 and $.41. Not sure if it is a mistake but I ordered(last week) all 8 springs for front and rear for a total of $11 including shipping.

[Dadevilledisco]

Ordered 2 sets of springs and RN sending a new cylinder to replace. Will report back in about a week when I have revisited repair!

[Dadevilledisco]

removed shoes, springs and cylinder anticipating RN package tomorrow! Cylinder piston on the trailing shoe was stiff and not as smooth as the leading shoe. Swapped 'em and figured that a sticky piston would do better against the spring but refuse to put it in since I got another coming in tomorrow but thought Id post what I found. Anyone seen anything like this before?

[jac04]

Anyone seen anything like this before?
Yes, I've experienced a sticky piston on a Genuine clutch slave cylinder.

[o2batsea]

There's a leading shoe and a trailing shoe which you need to get right way around. I assume that you did that. Also, on the trailing shoe you should slightly bevel the leading edge of the friction material.
Adjust the brakes so that there is some degree of resistance to turning with tires on and both wheels off the ground.
If the shoe isn't retracting when you let off the pedal then it must be binding inside the drum. The wheel cylinder won't push on one side more than the other, but it will push the shoe with the least resistance first until it engages the drum, then the other shoe until it too engages the drum. Usually this happens at the same time tho, so you don't notice it when applying the brakes.
I suspect the problem is the drums or the shoes aren't right somehow.

[Dadevilledisco]

Put on new wheel cylinder, upgrade shoes and new springs and everything is fine now! Gotta bleed and adjust and we are back on the road. Thanks for the advise and Thanks to Les for the parts and advise. I don't know the problem but feel like it was the cylinder. Like the upgraded shoes, gonna replace the LR when I get time this weekend.

[Les Parker]

Glad that all is now well with the RHR shoes/wheel cylinder.
Let us know how your LHR brakes work out.
RN always appreciated feedback, which ever way it goes, we all learn when we have the info.
Thanks again for sharing and the call this morning :)

[jac04]

Like the upgraded shoes, ...

Tell us more about the upgraded shoes. Are we talking about Genuine or Mintex versus Britpart?

[Dadevilledisco]

I think they were mintex? RN sells one for 29/set and I think these were 39/set or may 39/49.

New problem! I put on SS hose front and rear and just finished bleeding the brakes and The pedal goes to the floor and stops VERY slowly. I adjusted all the pedal travel when I put on the shoes. I had to replace the LHF rigid line which is done and did not touch the cylinders or shoes or adjusted them. I simply changed the freaking flex lines! While bleeding I feel the pedal build pressure and release but when we are finished the pedal hits the floor and the rover SLOWLY comes to a stop. I changed the fluid to Castrol synthetic and have completely bled the old fluid out. It has been about 4-6 weeks since I did that. Will the change damage my rubber seals that quickly? No leaks anywhere just a lack of pressure. Could it be the MC. Fluid is going down when we bleed. Do I need to recheck adjustment on shoes x 4? Pumping the pedal doesnt help much, it use to before I found my leaking rear cylinders I would have to pump the brakes every now and then to get a better grab on the brakes but no more than once and she was slowing down quick. Getting extremely frustrated with this as I have not been able to drive it around for 2-3 months.

Thanks,

Mark

[JackIIA]

Given that you already adjusted your brakes and all was fine, and then you replaced the flex lines and had problems, sounds like you still have some air in there, despite bleeding. By Castrol Synthetic do you mean Castrol GT LMA? That is the correct fluid to use so no reason that would damage your seals.