Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Rear brake drums - 4/4 2004

Hi all,

Today I have mostly been in my garage finally doing those repairs that I couldn't for various reasons in the summer. The car's been off the road since August but I'm hoping to get it all done in time for Christmas!

One of my MOT fails was the NSR brake binding. I've taken off the drum (it was easier than I thought it would be, having done this sort of thing before!) There are no leaks but other than liberally saying everything with a penetrating fluid (aka WD40), avoiding the braking surfaces of course, what else is there to do?

It could be the handbrake cable not letting go completely? If the damp has got in, it will start rusting, and even though it will work, the return springs may not be strong enough to release. Also lube all the handbrake pivots etc.

I should PM DaveW as he is the guru on maintenance on here .

Tease the rubber cover away from the cylinder, and see if there's rust or any reason why it's sticky. You may have to strip it down to free everything off, but as Paul has said, also check the handbrake cable.

Check that the wheel cylinders are retracting fully , sometimes they can stick a little way out from the fully closed position, and this can lead to the shoe binding slightly.

If they are suspect , then it probably would be an idea to replace the rubber seals in the cylinders. Once they stick it tends to form small ridges of dirt in the bores which can damage the rubber seals and then they will start to leak fluid.

Hi Julia, three observations from me, based on the photos, so I may well be off track.
1. The damp patches on the drum, was that as a result of WD40 or such like to get the drum released.
2. I would expect the drum surface to be more shiny if the brakes were operating correctly. Think of a used railway line vs unused railway line.
3. On second picture there does appear to be a damp area to the right of the left hand dust cover of the brake cylinder. If it is not WD40 or similar, it does suggest you have a small leak on the brake cylinder.
Apologies if teaching someone to suck eggs, Brakes are just too important not to comment.

If you are taking the brake shoes off, I would just give the back plate a good clean and smear a tiny amount of copper grease where the brake shoes will rub the back plate.

If the car is not used much the cyliders fail, but usually they leak fluid. My 4/4 did that after c 30k miles.
It all looks a bit rusty and under used.
New cylinders are cheaper than rebuilding, but it could be the cable.

Firstly clean that rust out of the drum frictional area with course emery cloth, sand paper will do if your stuck. Then before you start stripping anything down, mostly uneccersary, put a large screwdriver between the shoe and backplate one each side, difficult to explain but handles out towards you and the tip of the screwdriver at 90 degrees to the backplate. Put slight pressure on each screwdriver alternately and see if you can move the shoe, and the piston on that side of the wheel cylinder in a fraction, you only need to move it a small amount, and then the other side, repeat this about 20 times and it will show you if the wheel cylinder is seized or not. If the Pistons are moving keep moving them and they may just move in enough with the return spring pressure to cure the drag. Of course as others have said check for hand brake pivots and cable sticking by making the drum free and then putting on the hand brake and checking after release it runs free, now repeat with the foot brake. As a safety warning though if your in any way unsure please ask again or consider getting some help, steering and brakes need to be 100%, mess up the engine and the car stops, mess up the brakes.....you know the rest of this sentence ;-), help is here if you need it.

Julia

If you find you need some OEM parts as a result of your investigations p.m. me and I'll give you a good reasonable priced supplier that I discovered.
I am currently in the middle of a rebuild of the braking system on my 1999 +8 - being a bit fussy I would rather do this now than discover a failure when I'm on my Alpine trip next year. The car has only covered 25,000mls but both rear cylinders were lazy in returning causing rear brake sticking.
That left lower edge of your rear cylinder looks suspiciously like a weep to me as has been said earlier.

Good Luck.

Hi all and thanks for all of the information. A head start when I get out to the garage this morning for phase 2!

PaulJ - The handbrake is definitely a possibility as loosening this helped the removal of the drum in the first place so I will do it while everything is off, which always makes sense anyway.
DaveW - I add my thanks to the mounting pile of e-mails you must have. Your 'How tos' are almost essential reading and I have been following your easy guide for the rear shocks, that I'm doing at the same time as this brake problem. As you and Mog615 and Wirewheel have said, that cylinder will bear closer inspection today, along withe OS one while I'm at it. The photo does certainly look suspect now I've blown it up, and I don't think it's WD40 just there.
John (and WW again) - I'm fairly certain underuse isn't the problem. +100k miles in my 2004 car so far! She came off the road in August so I think there may be the surface oxidisation you get when you stop using things and the sand paper is at the ready for the rebuild phase, though the budget may stretch to some emery cloth instead!
SJ - thanks for the hint on the screwdrivers (and the PM) - I'd forgotten that one. Used to do that with the motorbike brakes 'back in the day'. My last brake project on the Mog was new discs a couple of years ago, though I did have to call for help just last weekend on the tin top - when did they start 'screw in' caliper pistons?!
4/4Sportsfun - thanks. I know HofE Morgan have cylinders in stock as I asked yesterday when ordering the shocks but I may pester you anyway.

I'll post updates later when I get back from the garage :xmashappy: