Shakin' Brakin'

[Guest timswait]

I've had my 2B (double wishbone) on the road for a year (6000 miles) now. When I built it I used the discs, calipers, and pads from the Sierra (they were all fairly good) and braking was fine to start with. In recent months however, a steering shake has started to develop when I apply the brakes. It started barely perceptable, and got worse, and is now fairly severe if I brake fairly hard from high speed down to 30, say. It doesn't happen at low speeds. I have the car off the road for an engine change at the moment, and was planning on replacing the brake compenents now anyway. I've checked all the bolts on the front suspension are tight (they are), pulled the wishbones about and they seem solid, and done the same with the calipers. Any ideas what's causing it, and how to stop it ?

P.S The pads have plenty of friction material left and there is no loss of braking power, only the shaking.

[Guest Twoscoops]

At a guess it sounds to me like your discs are warped..... you need to replace the discs and pads to solve the problem.

 

Bear in mind that the discs generally warp due to excessive heat or very harsh braking. Have a look at you calipers and pads to see if they are wearing unevenly. If so then it could be that you have a ceased piston in the caliper and the brake pad is generating the heat by constanting touching the disc even when your not applying the brakes.

 

If this is the case then you will need to service the caliper or get an exchange one (although more expensive, it is better in the long run).

 

hope this helps

 

Twoscoops

[Peter Bell]

I had the warping disc problem on a Sierra with vented discs, it got worse really quickly. They distort inwards where the vents are, hard to measure but new discs sorted it completely.

[Guest timswait]

Thanks, that was what I was hoping for, didn't want any suspension probs. Forgot to mention, my mate's Sierra has a very similar problem except it also does it at a certain speed (65 - 70 mph). The Sierra I'm getting my engine out of also does it.

[Big Jim]

It's just the Disc's, you don't need to change the pads (unless you want a change to different make) I'm on my 4 th set of disc's in 3 years, but at £10 each it's not worth bothering about.

[Mitch]

Forth set!!!! you are going to have to slow down earlier Jim

Mitch

[ibrooks]

Just a little aside here - I know the discs only cost a tenner each and are prone to warping in the Sierra but I wouldn't have thought it was such a problem in a lighter car like a Hood (maybe it's just because they are driven more "enthusiastically"). However on the cars where the discs are only held on by the wheel nuts I've seen them start to wobble suddenly after a wheel has been off. What has happened is that some of the collected cr*p from behind the disc has dropped down between the disc and the face of the hub. Try taking the discs off and cleanig it out before you splash on new discs - can't hurt.

 

Iain

[Guest timswait]

Where can you get discs for a tenner? Halfords were £20 each and Ford wanted to relieve me of twice that! Are the facts that you're paying £10 for them and that you've got through 4 sets in 3 years related?

[Guest Andy Sparrow]

My kit supplied disks only lasted 1000 miles (not all in reverse yes I do drive it fowards sometimes Jim!) So I went to partco & they quoted 11 quid for cheapies OR 13 quid for quality Quinten Hazel (spelling?) I figured the 'Quality' option might last longer and bit the bullit (well its only 4 quid and with my anual mileage they should last 425 years)

 

 

PS they were 2.0 vented (I didnt change the pads - but was advised that Green Stuff ? pads would be better (less heat) but they were another 25 Quid !)

 

As Jim says for the sake of a tenner (approx) whats the problem

[Guest Ant]

Gentlemen, may I add my two pence worth ...

 

"Steering" judder under braking is usually the consequence of worn steering bushes, ball joints, or similar components on the front suspension. "Brake pedal" judder is the consequence of warped or internally fractured disks. If you have brake pedal judder as well as steering judder then I'd blame the disks. If you have steering judder only then it's more likely to be suspension components.

 

On the Sierra's this was a classic problem. The bushes in the lower arms on the ends of the anti-roll bar were notorious for wearing out - often in 15k miles or less. This was made worse if any of the other suspension components were slightly worn. Under braking this caused the whole hub to judder forwards and backwards relative to the chassis. On the 2B I wouldn't expect this to happen as these bushes aren't there any more ... but I would expect a similar effect is the wishbone bushes were worn, or the ball joints were worn.

 

Steering judder at specific road speeds is normally caused again by worn suspension joints - on Sierra's this could be those anti-roll bar / lower arm bushes again, or the inner bush in the lower arms where they attach to the body.

 

If the disks are fractured internally (this normally happens on vented disks only) then once hot the thickness of the disk varies around its circumference. This makes the brake pedal jump up and down under braking - rather like what an ABS system does to prevent the wheel from locking up. Both scared the hell out of me the first time it happened. Fractured disks on my old CVH Sierra didn't cause any steering judder - only brake pedal judder.

 

I've not experienced warped disks (unless my fractured ones were warped as well as fractured), though I'd expect the brake pedal to judder as well as the steering.

 

Hope that helps to sort out different cases of a similar effect.

 

Ant

[Guest Andy Sparrow]

All I can add is that changing the disks cured the juddering on steering wheel ....

[Guest daveg]

All

 

Me too, discs cause steering judder when brakes applied (on a Fiesta, but priciple the same)

 

Dave

[Guest bloke]

i had a new punto an 6 months the same, confirmed by dealership

[Guest timswait]

Thanks all for your help, I'll be changing the discs when I finally get my EFi engine in and running. I'll tell you then if this solves the problem, and if not I'll take a look at the bushes. Like I say all seemed tight though.....

I'll pass on to my mate that info about the anti roll bar end bushes, I suspected them myself as they looked perished and I don't think he's ever changed them.

[Big Jim]

If you go to a proper 'Motor Factors@ you will only pay around the £10 mark, double it for Halfords, and multipy by the first number that comes into your head for Uncle Henry's gang!

Should you have to buy them in France, even Ford seem cheap!!

 

Just to confirm, I had the affending disks checked at work, and they were running out considerably.