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MG MG Y Type - Rear Brake Cylinder Stuck

Chaps,

I'm gutted - My old YT failed it's MOT yesterday for the first time in the 8 years I've owned it.

Everything was absolutely fine, but in the agressive braking that seems to be part of the test it appears that one of the "plungers" on a rear brake cylinder is stuck out.

Any advice please?
Likely causes?
Quick solution - can I just push it back in with a clamp or something and all will be okay?
Or will I have to repair/replace the cylinder?

Please help - need to get it done in time for a re-test within 10 days to ensure that I don't have to pay-out the excessive test fee again.

Cheers,
Saul.
Saul Duck

Saul

Have you got the roadwheel off and the brake hub? If not you will need to slacken the brake adjusters right off to get the hub off using a pry bar (two if you can get an assistant) behind the lip of the hub and then set up tension on it and beat the sides of the hub with a 3lb hammer moving the pry bar and the hammer around the circumference.

Cause - any number of things.

Remedy - dont to them!!

Serious bit: Yes if you slacken the bleed nipple off, and the dust rubbers are in good shape still you should be able to push the plungers back in. However better to find out what is really going on there and I would suggest:
1) Put a vice grip on the rubber hose and clamp it off
2) Remove the wheel cylinder completely to a bench
3) Strip it down on a bench. This will enable you to examine the inner seals and the pressure cup washers and the spring as well as the inside of the cylinder.
4) If the inside of the cylinder is rusted this will be because of water absorption into the brake fluid. Answer, switch out your brake fluid about every 2 years or so.
5) If it is only lightly rusted you may be able to clean it up with a fine grade glass paper but do not use too much pressure and score the inside of the wheel cylinder. Clean off any rust on the plungers too.
6) Reassembly - if the inner seals are torn - get a TC front wheel cylinder repair kit (it is the same) and either way, wet the seals and the pistons/plungers with brake fluid before reassembly.
7) On refitting to car after hook up, remove vice grip from rubber flexihose and bleed that wheel cyclinder and the opposite rear one too.
8) Adjust up the brakes on refitting hub.

Good luck

Paul

Paul
Paul Barrow

Thanks Paul.

I THINK the problem is due to the cylinder getting "upset" at having to come out too far due to my shoe getting near the wear limit on that side.

For new shoe linings am I correct in thinking the best route is to go for an exchange at NTG (K034X = set of 4 for £65 + VAT) rather than getting some linings and rivets and trying to do something myself that I'm going to mess up (K202T = £30 + VAT).
I notice Moss do shoes (182-110). I think they are outright sale rather than exchage but at £66 I am presuming that this is for a pair rather than 4?

If NTG exchange is the best bet then how does that work? Do I have to send them my old shoes first?

I've got just one week of cold dark evenings to sort this.

Cheers,
Saul.
Saul

Saul

I would give Fraser Hook a ring at Chelsea Frictions, his telephone number is 07986 686353. Frazer is the chap with the huge military vehicle that you see at Beaulieu, Enfield etc. Frazer will fit new linings to your shoes or has them (exchange) in stock, or did last time I saw him. Remember the brake shoes on a YA/YT are the same as on a TC so they are quite popular.

I have used him in the past for my YA, YT, TD & VW Beetle and can recommend him. In fact I did and he is on the website but the info needs updating.

Regards.

David (prman AT mgytypes)
David Pelham

Saul: Paul's description of the task you are taking on is very comprehensive - I'd only add one thing. When you are reassembling the wheel cylinder, apply a little copper grease to the sides of the pistons (what you're calling the plungers), outboard of the rubber seals. Copper grease is compatible with brake systems, and it can reduce the ingress of moisture to the brake system from the atmosphere- which is what caused the problem in the first place. And apply some copper grease to the lips on the protective dust seals: this adds another layer of defence.

It may well be that the wheel cylinder on the other side of the car is suffering from the same problem - to prevent a potentially dangerous imbalance you may want to check it out. Obviously, you'll be relining the other brake anyway.

You will be surprised at how much more responsive the rear brakes are once the wheel cylinders are operating as they should - the results can be seen on the MoT test meter.
Tim Griggs

This thread was discussed between 17/10/2008 and 06/11/2008

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