Page 6 of 7

Re: Steering shudder on braking

Posted: 20 Dec 2017 08:40
by hugejp
I would love to have seen that!

Re: Steering shudder on braking

Posted: 12 Jan 2018 13:46
by Clem
Problem solved. Wheel balancing. I had had the wheels balanced at my local Minty's so had eliminated that as a factor. But went down to TWaT Rontburg this morning. Wheel balancing was waaay out. Turns out the balancing machine needs calibration every morning. I didn't know that. Anyway, lesson learned: check the basics and check them again! Oh, and try to find a place that is on the ball. FWIW, TWaT couldn't check the wheel alignment - their software for the Patrol only goes up tp 2010. :-(

Re: Steering shudder on braking

Posted: 28 Jan 2018 11:24
by Clem
So much for that theory of mine. Issue is still present.

Okay, I'll have to check castor and toe-in. Anyone know of a place with machines with up to date software? TwaT Randburg only have GU specs to 2010. May be - should be - the same but utterly no point if there is an unknown variation.

Re: Steering shudder on braking

Posted: 29 Jan 2018 07:16
by Tinus lotz
Auto wiel Centurion west barend will help you

Re: Steering shudder on braking

Posted: 29 Jan 2018 09:11
by Clem
Thank you Tinus.

Re: Steering shudder on braking

Posted: 10 Mar 2018 15:35
by Clem
Okay so I went to see Barend today. The vehicle still has positive caster (0.07° whereas specification is 0.5°) but according to Barend that is fine provided the vehicle doesn't pull in either direction – which it doesn't. The vehicle was slightly toe out and so we had to adjust it to 1.8 mm toe in. So it's now perfectly correct. But it doesn't look like the shudder has gone away, although my sense is that it is a little better – but I need to drive it a bit more to be sure of what the situation is. In any event, the next thing I am going to do is have the brake discs skimmed (the vehicle has 46,000 km on it, so it is possible that this needs doing). If that doesn't solve it, then I will have to ask Graham to check swivel preloads and the like.

Re: Steering shudder on braking

Posted: 10 Mar 2018 17:25
by Tony
Hi Clem, I have picked up a similar thing - a shudder on the steering wheel, but only noticeable on those long downhills on the Cape's mountain passes. I don't pick anything up with normal everyday driving, hard, short braking etc. As soon as i'm on a long downhill and have to brake the steering starts to wobble. I have just replaced my old BF's (305 65 17) which were seven odd years old, and impossible to balance properly for long, with Cooper ST MAXX (285 70 17) aligned by Barend, but balanced on the Hunter Roadforce (R 1 Mil) wheel balancing machine at TWAT in Sandton - (The only one in Gauteng) It will be interesting to see what difference they will make. I have a service scheduled with Graham and have asked him to check whether the disks need skimming as well before our next trip down to Slaapstad end of April.

Re: Steering shudder on braking

Posted: 10 Mar 2018 17:46
by Peter Connan
Clem, mine had a bit of a shudder under braking for pretty much ever.

A little while ago, I tightened up the steering box, just a little more than I normally do. Problem solved!

Just tighten it up a smidgen, even if you think it's still fine.

Re: Steering shudder on braking

Posted: 10 Mar 2018 18:46
by Clem
Thanks Peter, that's very useful. I'll check it out.

Re: Steering shudder on braking

Posted: 11 Mar 2018 08:35
by Clem
Peter, this may just have solved the issue. This car has always had a pretty light steering and Graham also noted its propensity to very slight lateral motion (i.e very light or only just perceptible death wobble) on the freeway. I've tightened the steering box 3/8ths of a turn and it seems much better. Now the steering is firmer but I can still quite easily steer the car rolling down a slight downhill with the power off - which tells me that I've probably not over-tightened it. Also braking from 80km/h hard enough to get the ABS to operate (I tried it twice) there's no shudder. We'll see with time what the situation is. I'll now mark the current position of the screw.