Steering wheel vibrates on braking

Post by **tingo** » Sun May 31, 2009 8:09 pm

Hi, I've recently replaced both rear wheel cylinders and adjusted the brakes all round so that they stop the car much better than they used to. I have not changed the drums or shoes which all look OK - 8" drums on the front. It has just passed an MOT following the adjustments.

Now, if I brake sharply from 40mph+ - especially whilst turning, the steering wheel judders until the speed comes down below 30mph. It doesn't happen with gentle braking or at slow speed. Is this normal? If not, what should I check first?

Post by **bmcecosse** » Sun May 31, 2009 8:59 pm

Not normal - and would usually be the front brake drums gone slightly 'oval'. But could also be loose suspension parts/king-pins/trunnions etc - although if just passed MOT it should be ok.

Post by **taupe** » Sun May 31, 2009 9:25 pm

I know this is obvious but are your wheel nuts loose on a wheel.

I had exactly those symptoms once after adjusting brake and tightening nuts by hand - forgot to torque one wheel!!! it took about a week to come loose enough to notice and I ended up with a scrap wheel and studs.

I now have a routine that I dont put the nuts on until Im ready to tighten them.

Post by **tingo** » Sun May 31, 2009 10:15 pm

Thanks for the replies.
taupe - I've checked the wheel nuts, they are fine.
bmc - when you say "loose suspension parts" do you mean "worn" or that something needs to be tightened?

I think it is most likely to be oval drums which would not have shown up when the brakes were working poorly. Will check everything over on the front suspension, just in case.

Post by **bmcecosse** » Sun May 31, 2009 11:01 pm

Well - could be worn bushes etc - or worn trunnions - sometimes the MOT places don't know what to look for! To check drums - fit them to the hub 'inside out' - then spin with a simple fixed pointer used to determine if they seem 'oval' Sometimes a simple swap from one side to the other can make a difference.

Post by **kennatt** » Mon Jun 01, 2009 8:06 am

if it was the drums would suspect that you would feel it through the brake pedal,if on the steering wheel more likely suspension,could be the track control arm bushes

Post by **sirrom** » Mon Jun 01, 2009 10:06 am

Sounds like brake drums need skimming to make them round but you probably feel it in the brake pedal but as others have said about other suspension parts worn or loose - check the rubbers on front of the tie bar

Post by **Stig** » Mon Jun 01, 2009 10:11 am

Thirded re. the tie bar rubbers. I had similar symptoms and replacing the tie bar bushes sorted it.

If you're in a hurry, as I was, you can do just the front one of each without removing the tie bar or even jacking the car up. One split pin and nut each side is all. I really should replace the other two bushes but it's the front bush that gets the braking forces.

Post by **rayofleamington** » Mon Jun 01, 2009 11:28 pm

if on the steering wheel more likely suspension,could be the track control arm bushes

got all the good responses so far. Nearly all Minor front brake judder is related to the tie bar rubbers and unevenly worn drums. Mostly it's a combination of both but whichever is the major factor will need replacing. If you replace both I bet you'll have cracked it.

Never ever bother skimming Minor 8" drums. Replacments are cheaply available and give a far better result. Skimming will increase the inner diameter (causing shoues to fit poorly, and limited adjustment range) but even more seriously it will reduce the thermal capacity, giving you brake fade even quicker. Added to that, if the uneven wear is due to a hard spot in the casting, the uneven wear will come back.

Post by **tingo** » Tue Jun 02, 2009 8:02 pm

Thanks for all the advice. If anyone has a Haynes manual handy could you confirm that the bushes are the ones on page 147 labelled "63 Bush to frame (rubber)"?

I'm going to try the inside-out brake drum trick.

Post by **tingo** » Tue Jun 02, 2009 10:29 pm

I've checked the bushes. I've got a brand new pair on the side where I've had a new chassis leg fitted. The pair on the other side are best described as "crispy"

The brake drums are not exactly oval, but there is some uneven wear. The edge moves in and out by less than 1mm as I spin the drums with them fitted inside-out.

The good news is that I seem to have cured most of the problem by taking it all apart and putting it back together. I think that I will get a new pair of bushes anyway.