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Brakes or something else


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So it's coming up to MOT time so I've been checking the car over for faults. All seems okayish. However my brakes are little odd. Sometimes they work well and other times the pedal goes solid (can't push it any harder) and the brakes aren't doing much. Which makes me think air in the system? Or could it be a faulty vacuume pump or master cylinder. I've changed the servo recently as it was leaking so I know it's not that.

2nd is it pulls to the right when braking. So there is a fault on the left brakes. How do I tell if it's rear or front? And how do I confirm its the brakes? Someone suggested to me it could be the swivel joint or CV. Or could it be the air in the system?

Cheers

Stephen

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I know this might be stupid but how easy is it to stick on the brake tester with it being a 4WD? When they done the last MOT he didn't check it on the brake tester but took it out a drive.

Oh also it's a 1986 90 with a 300tdi. It's fitted with a 110 servo and master cylinder. Just incase that makes any difference

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Ah okay perfect! If it is the Pistons that have siezed how do I work out which ones I need and how do I know which pads. I've not had the car long enough to work out what's standard and what's not :(

Is there any obvious tells? Piston size or pad size?

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Remove the brake calliper and leave the brake pipe connected.

Flip it over so you can see the pads.

Place a spanner or something between the pads that is about the same width as the brake disc, if you do not do this there is a danger that the pistons will fall out.

Get someone to push the brake pedal and watch the brake pistons come out as pressure is applied to the pedal, they should come out even and smooth.

You should be able to see if a piston is sticking at this point.

As for the pads they should be the same width at both sides – if not I would replace them.

Also check that the pads are dry as the pistons may be leaking fluid.

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So I took the passenger side front wheel off today and had a look at the brakes. Now I had known I had a leaking swivel housing but didn't realise how bad. The inside of the disc has a lovely coating of grease as did the pad. The outside edge was okay.

So Im going to clean it up and stick it back together but obviously need to fix the leak and replace the pad (the disc should clean up okay I think, could someone confirm? Just with break cleaner)

Which pads do I need? I had previously ordered STC9145 but that wasn't the right one. I think I need STC9191. I have included a photo (They look the same but obviously you can't go by looks all the time!) Its a 1986 90, drums on the rear.

And now my next question, whats required to sort my leak on the swivel? Would it be this or would I need to replace the ball as well or something else? Or do I need to provide more info for someone to be able to tell me? Sorting this will be the biggest job I will have done. I know there are videos on youtube about it so I will be watching them a few times! But any tips would be useful and a hand to sort the parts!

Cheers

Stephen

post-98616-0-61448700-1451681646_thumb.jpg

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That kit has more parts than you need to fix the leak. The leak is either the seal (in the kit), security of the seal (retainer ring, not in the kit) or the surface condition of the chromed ball over which the seal moves as the steering and suspension cause that movement.

To replace the seal you normally remove the swivel / hub assembly as a whole, which requires you to remove it where it joins the axle. You withdraw it along with the drive shaft too. This then gives you access to the seal retaining ring and the seal, both of which can be lifted away from the swivel housing and over the drive shaft. Releasing the small retaining ring screws can be a bit tricky too (damage) and they are better replaced on reassembly, along with a new retaining ring.

If the leak is caused by the surface condition of the ball (chrome is pitted) then it is possible to clean this up by using a metal paste like Devcon in the same way that you can fill body dents with filler. If you can't restore the surface finish sufficiently then you would need to replace the ball.

The other items in the kit you linked to allow the steering preload to be reset by providing a new bush for the top pin and the shims required to adjust its tightness. Plus it has the bearing for the bottom. So you don't necessarily need to do this if the steering pre-load is OK and there's no play in the pins.

Others will be along to add to and correct my basic experience.

As for cleaning the pads, I would just replace. They look very badly contaminated and although brake cleaner might work (think it's used as a fuel to burn off sometimes?), I would have though that new pads isn't too extravagant.

I should add that it is possible to replace the seal with everything in place - by cutting it so that it can be slipped over the axle, then positioning the cut at the top so that it is above the level of the oil or grease in the housing. That is a cut to the rubber and the supporting spring inside the seal. I've never done this but i don't see why it wouldn't work and it's certainly a quicker solution if that's all that is needed.

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So I have been for a look in some daylight and well its worse than I thought! The ball is badly pitted so looks like I might as well just rip it all out ad start again! So I guess now need This Kit and a spare day! While I'm in there and have it all stripped down should I do anything else? I'm thinking CV joint? And maybe the disc? Don't want to have to pull it apart in 3 months because one of them has failed!

I will also check the breather to make sure its not blocked and this wasn't all caused by pressure build up in the axle.

Stephen

(Changed swivel kit to OEM)

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Im sure this is an impossible question to answer but does anyone know how many splines my CV will have? I don't know how to tell other than pulling it off but I'd rather leave that for when I'm doing the work. I wasn't sure if there is a way to tell from dates or if its just what the factory were using at that time.

S

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The CV is easy to change another time if you want to spread the work - just drain the swivel lubricant, remove the drive flange and pull the driveshaft out of the axle.

If you go for the kit you show, don't forget that you will almost certainly need a new seal retainer and the screws to go with it. I had to use miniature stillsons and heat to slacken mine and they got chewed.

You will also need to be ready with a new set of 12 point screws for the connection between the housing and the flange on the axle. I think these have 14mm heads and undoing them is only really possible with a ring spanner - a long one or something else to give you the leverage. They are very tight and a socket won't fit as it is fouled by the flange.

As for other work you could be prepared or you could do another time. Discs - look at the surface condition and if they look worn, measure the thickness and compare with the minimums advised in the manual. Callipers - check for leaks and pistons that move. Flexi brake pipes - again check for leaks etc. - but these things can be done separately. It all depends on what time pressure you have / and their respective conditions once you start looking!

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  • 2 weeks later...

So Ive changed all the swivel bits and bearings and everything, changed the pads on both sides, also upgraded to the steel flexible brake pipes or whatever they are. Also had to change the calliper on the drivers side as the wiper seals were dropping out and I couldn't push the pistons in.

Took the car out for a drive and wow its much better, skidded a lot when I push the brakes hard which it never done before! However its still pulling to the right, enough for an MOT fail. So I'm guessing its the calliper? Going to have someone step on the brakes while I watch the pistons but could it be anything else?

S

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Just wondering. I recently changed the swivel housing and had to re-shim the top bearing, I couldn't get both the steering rods off the housing so done it with one in place. Meaning I couldn't get a proper feel for the resistance, if I've put to many shims in could this be the problem? There's more resistance, or less on the left wheel causing it to pull in?

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