Brakes make me wanna top myself......

Guru Meditation · Unread post by **Guru Meditation** » 12 Jan 2003, 07:40

I've posted a couple of times about my new vehicle a '93 K ZX Aura TD. I'm pretty pleased with it on the whole. Since I've had it I've done basic maintenance-oil and filter change, fuel and air filters, timing belt change (took me 6-7hrs

) still to do coolant change, transmission fluid change etc.
It has a problem that is really spoiling my enjoyment of the car and is driving me nuts. When I got it the brakes juddered badly and lacked stopping power. I thought it was just sh*gged discs and pads, no problems. So I fitted some sh*tty Ha*fords discs and pads (I know, I know but it was convenient...). It was immediately apparent that the brakes still juddered. After 150-200mi bedding in the brakes behaved like this:- Stopping power was as good as I'd expect, braking from high speed (70-80mph) there was good bite and no vibration but as i slow there is a vibration which rattles the car, can be felt through the pedal slightly and totally spoils the feel of the brakes, also doesn't seem to be quite the bite and easy stopping power I'd expect from low speed. A passenger in the car would be able to hear and 'feel' the vibration. I thought it was just the poor quality halfords discs as although there was judder as before it was nowhere near as pronounced and the brakes were a lot more powerful. So I bought some Brembo discs from Andyspares and fitted them. When I fitted them I ensured the hub was scrupulously clean and flat and disc mating face clean etc, retaining screws in place, calipers on and bolts torqued up, copper grease on backs of pads etc. But surprise surprise the vibration is still there, the brakes feel sh*t. The stopping power is there but at low speed (<50mph) there is still pronounced vibration through the car, pedal, car doesn't feel like it's biting and stopping like it should.
I don't know what it could be! With the wheels off I can say that there was no detectable play in wheel bearings/hubs, drop links for anti roll bar fine, track rod ends look spot on, no visible play in suspension, gave a tug here and there all seems fine. Tyres correct pressures, wheels not been balanced but the balance must be fine because there is no vibration through steering at any speed from 1mph to 110mph under acceleration of deceleration. The car drives in a perfect straight line at any speed, doesn't pull either way, tyres worn evenly, also under braking light or heavy the car pulls up in a perfect straight line implying that the calipers are fine (no leaks etc seem to slide fine).
I haven't checked the back brakes yet (drums). Could they cause this kind of behaviour by out of round drums etc?
It is really doing my head in so any ideas of what to check etc would be gratefully appreciated. I'm determined to get to the bottom of this if I have to replace everything-it's really wrecking this car for me.
Cheers
Guru Meditation

Unread post by **alan s** » 12 Jan 2003, 12:08

I've just cured a similar sounding problem on our Mazda/Ford MPV that had driven me & a lot of other people insane for ages.
We had done the steering rack, new pads, steering box and wheel balance. I had been told it was possibly discs "running out" that also wasn't the case.
We had a tyre scrub due to someone else driving who was not used to forward contol operation & bingo, the problem went. Closer inspection proved it was a tyre out of round. Didn't show up even on a tyre balancer unless the guy who was balancing the tyres (and who also sold them to me) didn't want to see it.
May not be the problem but worth looking at just the same; any port in a storm.
Alan S

David W · Unread post by **David W** » 12 Jan 2003, 13:18

GM,
My first port of call would be tyres like Alan. So many times I've had folks with odd vibrations that they say can't be tyres, often because they have been balanced and check out OK. Even if you take them for balancing the tyre guys so often say they are OK, they don't seem to understand that they can balance out a lump in free air on the machine but as soon as it runs on the road you'll feel it.
You need to jack up and slowly rotate each wheel and look for an odd lump or twist to the tread. This is much easier if you stand something like an axle stand against the tyre so you can see how much any uneven tread is out.
Yes it could be the rear drums, less likely than discs but I have had it before.
Halfords discs needn't be terrible...a lot of their stuff is OE supplier made.
Any weak bushes in the suspension can increase the judder set up when braking.
Has it got ABS?
Good luck.
David
Edited by - D J Woollard on 12 Jan 2003 08:20:58

Dave Burns · Unread post by **Dave Burns** » 12 Jan 2003, 15:44

Yes the rear drum brakes can indeed cause this sort of behaviour, but they don't even need to be out of round to do it.
If the shoes have been or are getting contaminated with grease or brake fluid, when combined with the dust in the drum it can leave tacky spots on the friction surface of the drum.
As the brakes are applied and the shoes come into contact with the rotating drum, any tacky spots will tend to grab at the shoes causing eneven braking and pedal feedback, I have come accross this condition several times and have noticed that its more pronounced at lower speeds, the remedy is to degrease the drums and renew the shoes.
Dave

Guru Meditation · Unread post by **Guru Meditation** » 12 Jan 2003, 17:30

Thanks for the advice so far. The car doesn't have ABS brakes. Unfortunately I can't say for certain if my discs have excessive run out or not as I don't have a dial test gauge but I'm going to check out the tyres-I've got a 205 1.6 gti sitting there looking a bit sorry for itself-I'll bung the wheels on the ZX (stock gti 14" rims 185/65 section tyres) and see if it's the wheels/tyres that are causing the problem. Also I really need to check out the rears like you say Dave-if the rears have been 'looked after' like the fronts had when I got the car they may well be in sh*t state.
Guru Meditation

wheeler · Unread post by **wheeler** » 13 Jan 2003, 03:58

try pulling the handbrake on when driving and see if you feel the vibration through the handbrake lever,if you can feel it that will point to the rear brakes.in the past i've had warped hub flanges (usually caused by heating them to remove the old part of a wheel bearing) causing the same symptoms as warped discs. this can also warp a new set of discs very quickly,so you may have to replace the discs again if this is the problem.

Guru Meditation · Unread post by **Guru Meditation** » 13 Jan 2003, 16:42

Good thinking Wheeler-never thought to try that! Tried it this morning on the way to work-it elicited some interesting results. I'm still not sure if the rears are the cause of the vibration but having tried the handbrake test I'm sure they are shagged. Occasionally under braking I had also been hearing a really, really loud 'rubbing' type noise that filled the whole cabin that I couldn't figure out what it was or whether it was from the front or rear (thought it was brake related but didn't know how). Well pulling the hand brake on at 30mph brought about this same horrible noise. It's difficult to describe-it sounds like a really loud metal on metal chaffing, rubbing type noise. This is complete with some vibration etc but I'm still not sure if this is what is causing the vibration I feel under normal braking. I'll have to have a look at my rears they must be shot-dunno if it's shoes to the rivets, out of round/badly worn drums or spots of grease/tar like Dave suggests. Oh also the handbrake didn't pull the car up too sharp either-don't get me wrong I know handbrakes are much weaker than the normal hydraulics but put it this way-I wouldn't wanna have to stop on the handbrake from 80mph if my normal brakes failed! Also 15-18 clicks to hold the car firm on a gradient isn't properly adjusted is it?!

wheeler · Unread post by **wheeler** » 14 Jan 2003, 04:37

it sounds like the linings may have come off the shoes,get the drums off and have a look then replace the shoes if necisary,give the backplates & drums a good clean up and adjust the shoes & handbrake properly (about 4 clicks is more like it).after that try the same test with the handbrake,if you still feel it your probably looking at warped drum(s).

Unread post by **Jon** » 14 Jan 2003, 13:52

This is a ZX with vented front discs, and Girling calipers, yes?
I agree firstly that an urgent priority would be to get the rear brakes done from what I've read here.
I'd also be having another look at the front brakes as I have had similar problems with this set up, vibration, pulling to one side etc.
Have a look at the front caliper sliders. Very often on this caliper they are either partitially or completely seized. They may have been just free enough for you to get the new pads in I suppose.
On my old ZX Volcane (same calipers) I very carefully removed the rubber dust cover from the slider, and found that the slider bolts could not move in and out, indeed one was so seized that I had to resort to some (careful) heat to free it. Once free, the slider bolt can be removed,cleaned/derusted and refitted with the appropriate high temp grease (I actually used copaslip).
The difference was marked, car pulled up straight, pedal felt better and no vibration (although I did fit new discs and pads at the same time).
It may be an area to check after the rear brakes are fully sorted.
Another thing to check would be the condition of the front arm "P" bushes, if they are really worn the arm can move during braking causing all sorts of problems.
Jon Wood
[email protected]

David W · Unread post by **David W** » 14 Jan 2003, 14:34

Thinking about the rear brakes again for a moment I do find the first time I see many ZXs/306s the rear brakes can be in terrible condition. Because of a tendancy for them to go years without the drums being removed even cars with current MOTs have all sorts of problems.
Quite regularly I pull the drums to find weeping rear brake cylinders and contaminated shoes. Then when changing the cylinders you find the brake pipe is seized into the back and those need replacing as well. Also about the same time the handbrake cables outer cover has split leading to sticking so you might as well do them while it's all in bits.
What seems like "a little look at the brakes" gets expensive/time consuming!
David

Unread post by **Jon** » 14 Jan 2003, 14:39

I'm with you there David.
When I did the rear brakes on the Aura (and bearing in mind it had already had shoes, cylinders and cables once in its life before I got it) I had to replace all this lot again, plus the brake pipes. I also got my mate to whizz the lip off the inside of the drums on his lathe otherwise would have been in for a couple of drums too.
I would definately be off to Citroen for a pair of rear brake pipes before I even LOOKED at the wheel cylinders!!!
<img src=icon_smile_sad.gif border=0 align=middle>
Jon Wood
[email protected]

Guru Meditation · Unread post by **Guru Meditation** » 14 Jan 2003, 15:52

Despite having said earlier that I wasn't sure if the rears weren't causing the vibration having done further handbrake tests I'm now convinced they are definately the cause of some severe vibration! When I pull the handbrake on there is vibration that judders the whole car-very similar to what I feel under braking. As I was paying particular attention to the rear brakes I noticed as I let off the hand brake on a slope the rear suspension doesn't seem to settle evenly-like one side of the car is being released before the other. Surprisingly the car still pulls up in a straight line-or it doesn't deviate enough to feel the tug through steering at any rate. Despite being mega rusty on the exterior the calipers slider bolt gaiters are intact and the caliper seems to slide fine (don't fancy my chances of ever getting the caliper brake pipes undone without breaking them though) also my pad wear warning wires are broken on both sides.
I don't know if I can be bothered to mess around-I'm thinking of just buying two new drums, shoes and wheel cylinders and brake pipes and fit the lot on saturday. Question. What brakes are most likely fitted to the rear of the car-Girling or Bendix? Also does anyone know if Andyspares drums have the wheel bearing in them already? Brakes are such a pain!
Guru Meditation

Unread post by **Jon** » 14 Jan 2003, 16:12

To check whether its got Bendix or Girling rear brakes without dismantling:
Look under the car at the back, look at the backplate, in particular where the brake pipe goes into the wheel cylinder. If the wheel cylinder is round in shape here, then its Bendix. If its an Oval shape then its Girling.
Afraid to say that drums do not come with wheel bearings fitted.
You may get away with the drums anyway, some people very carefully linish off the lip I have heard.
Jon Wood
[email protected]

FFX-DM · Unread post by **FFX-DM** » 14 Jan 2003, 16:28

The whole things sounds terribly like when the linings came off from the rears on my AX. It happened after a lot of driving though floods. Anyhow, result was vibrations and nasty graunching noise. I confess that I was lazy and paid a chap to do it all for me, but that neccessitated new drums on both sides. A few (12)months later I noticed that the brake fluid level was going down and that turned out to be a knackered cylinder, and the shoes were contaminated. I paid the same little man to do that too. If you do it yourself, it may be worth doing both at the same time. I noticed a pair of ZX cylinders for sale on Ebay yesterday (cheap).
Interestingly, my chap got the wrong shoes, so he had to scrub and clean up the existing one sand refit them as I needed the car. Ages later, I thought I should get them replaced, so I went to Kwik Fit. After they had had the car long enough for me to watch England v Denmark, I rang them up and the bloke said 'oh no, I have looked at them and they don't need changing, come and pick up your car when you like and there's no charge'. It must have been right as it passed the MOT a couple of weeks later. Now this must be a first, as usually Kwik Fit try to sell me all sorts of stuff that I don't need bases on the premise that I am a girlie and know nuffin! Amazing!

Guru Meditation · Unread post by **Guru Meditation** » 14 Jan 2003, 22:13

Had a look at lunchtime-looks like I've got Bendix rears-the wheel cylinder looks to occupy a large circle rather than an oval-I'll soon find out if I've bought the right kit!!
I think I'm going to buy some shoes then have a look on saturday. I'll go for a degrease all round and reassembly with new shoes, unless the drum has a very big lip or scorring etc of course if anything else looks dodgy like the wheel cylinders I'll get some new ones to replace them. Of course if after a degrease and new shoes it still vibrates then I'll have to buy more bits. What are my chances of removing the old wheel bearings and getting them into some new drums intact or do you reckon it's a new bearing jobbie?