Steering Shake When Braking

[plastic orange]

Since getting new tyres fitted to the front of my car last week, I've noticed a bit of a wobble whilst braking. It isn't too bad under hard braking, but when just check braking for a corner it starts. The car was just Mot'd last month, and no wear was detected in the front suspension, and the discs look in particularly good nick.

I'm going to have a closer look, and perhaps see if the discs are warped (dial gauge).

Any other ideas?

Hopefully when this is sorted the car should be fine for a bit as I've spent a fair bit on it since buying in November.

Pete

[kenmac]

I suspect front suspension, my car passed the MOT in November and I have just changed my complete front suspension end it was the worst I have ever seen, so don't think as its passed its all OK.

[Redsteve]

Since getting new tyres fitted to the front of my car last week, I've noticed a bit of a wobble whilst braking. It isn't too bad under hard braking, but when just check braking for a corner it starts. The car was just Mot'd last month, and no wear was detected in the front suspension, and the discs look in particularly good nick.

I'm going to have a closer look, and perhaps see if the discs are warped (dial gauge).

Any other ideas?

Hopefully when this is sorted the car should be fine for a bit as I've spent a fair bit on it since buying in November.

Pete

Hi Pete,

I am interested to see what people have to say about this problem as I have it too.

I can feel the car almost pulsing at really slow speeds when I am braking.

I read somewhere on this site that the discs don't actually warp but they get spots on them that are "sticky" so when you brake the pads don't grip the disc with the same frictional properties all the way round the disc.

The "sticky" spots are caused when you stop the car and the brake discs and pads get hot and you don't release the brakes. The hot pads sit on the hot disc and the residue from the pad becomes burnt onto the disc.

Hope this helps.

Redsteve.

[plastic orange]

I get no clonks at all from the front suspension. The discs were replaced around 40,000 miles ago, and pads around 20. I know it's a heavy car, but I'd expect parts to last longer than this.

Pete

[Redsteve]

I get no clonks at all from the front suspension. The discs were replaced around 40,000 miles ago, and pads around 20. I know it's a heavy car, but I'd expect parts to last longer than this.

Pete

I think cars with Auto Trans seem to suffer with the spotted discs as people tend to sit with their foot on the brake while stopped to stop the car creeping forward.

As the LS is such a big, heavy car even light braking will generate huge amounts of heat in the pads and discs, therefore, wearing them out quite quickly.

It is just one of those things that goes with running a heavy, but fast car.

Redsteve.

[SteveLS400]

I get no clonks at all from the front suspension. The discs were replaced around 40,000 miles ago, and pads around 20. I know it's a heavy car, but I'd expect parts to last longer than this.

Pete

I think cars with Auto Trans seem to suffer with the spotted discs as people tend to sit with their foot on the brake while stopped to stop the car creeping forward.

As the LS is such a big, heavy car even light braking will generate huge amounts of heat in the pads and discs, therefore, wearing them out quite quickly.

It is just one of those things that goes with running a heavy, but fast car.

Redsteve.

Greetings

Over the years I have had big auto's than anything. I also well remember being taught not to sit with the foot on the brake on an auto and never to sit with the clutch down on a manual or to slip the clutch to hold it on a hill. Similarly that applies to holding an auto on an incline. BTW I grew up in Sheffield where everywhere is on a hill! But B$ I get an off topic.

Having had 3 Rover 827 autos ( and dont knock em, I had 1 crap 1 and 2 dreams) and the V6 was excellant..... digression again, there were quite a few posts about holding the car on the foot break and it was concluded that to do so did warp discs as well as putting strain on the breaking system. So there you are on a cold morning, engine on warm-up, aircon on etc etc. You are holding back a beast. Is it any wonder that problems occur.

I almost always slip in to N or if necessary, P. So no doubt someone will say "why have an auto" Reply? Why arent all cars made this way?

Was that a bit of a rant? In 35 years and maybe an average of 20k a year, never had warped discs.

And on the subject (must be a rant) whilst learning to drive, I was told that never ever ever should I a) pull the handbrake so hard and never to pull it without pressing the button in. Next time you are in the supermarket carpark just watch whilst others try to pull the floor up click click click........... Then observe the ones that did earlier. These are the ones who cant get the handbrake off when they come back off holiday.

Lesson. Dont hold the car on the brake unless you like servicing bills.

I have 2 unconnected rants so might post them in a more appropriate place in due course.

Ranting of Sleaford.

[plastic orange]

I've had quite a few big autos too, and was told not to put them in neutral (i always did up till this point) whilst stuck at traffic lights etc - Saab in particular caused problems over time apparantly (governor seals).

I suppose it really depends on the auto box concerned. I certainly slip my Minor V8 into neutral when stopped and may do the same with the lexus now.

Pete

[SteveLS400]

I've had quite a few big autos too, and was told not to put them in neutral (i always did up till this point) whilst stuck at traffic lights etc - Saab in particular caused problems over time apparantly (governor seals).

I suppose it really depends on the auto box concerned. I certainly slip my Minor V8 into neutral when stopped and may do the same with the lexus now.

Pete

Ok Pete, thats interesting. Lets see what other comments we get. I am hoping for a post which categorically proves otherwise.

Calmer of Sleaford

[Redsteve]

I slip mine into Neutral if I am stationary for more the a few seconds. If I am at a set of lights which I know take a long time to change then I will put it in Park, I usually have a bit of a giggle when the lights turn green, I look in the mirror and slot it into Reverse and watch the panic as the person behind thinks he is about to get a bill for driving into the back of my car.

Purile, I know, but it keeps me entertained.

Redsteve

[plastic orange]

Took it out for a test on the local dual carriageway (quiet) and noticed that it doesn't wobble until braking at over 60. There is no pulsing of the pedal, but when I did a quick stop from high speed I got a fair bit of knocking from the front end, but nothing through the pedal. I guess it wouldn't be any harm to do the top control arms - are the ones for £100 on eBay any good?

Pete

[Seb Harvey]

I've had this problem and it is because the discs are warped.

New discs and changing your driving style is the only way to solve the problem. Though when I last had the problem, I took it into a Lexus garage who skimmed the discs which solved the problem. This only cost £120 from them.

Problem is heat spots developing on the discs from keeping your foot on the brake at the lights or stationary, as the pads grip the disc and lock the heat in, which changes the shape of the discs.

The easiest way to find out if your discs are warped is to jack the car up and spin the wheels. As the wheel rotates you will notice the pads scraping the at a certain point during the rotation.

Suspension isn't the problem.

[SteveLS400]

Took it out for a test on the local dual carriageway (quiet) and noticed that it doesn't wobble until braking at over 60. There is no pulsing of the pedal, but when I did a quick stop from high speed I got a fair bit of knocking from the front end, but nothing through the pedal. I guess it wouldn't be any harm to do the top control arms - are the ones for £100 on Ebay any good?

Pete

Use the search function for "control arms" in the Suspension forum. There are loads of threads and quite a few with regard to suppliers and price.

Steve

[plastic orange]

I've been doing my research :D .

Strange that it suddenly happened when I fitted new tyres. I've never been hard on brakes in any car or bike I own, prefering to anticipate the corner and power round. Having said that, I'm certainly not slow, but try and be smooth, so perhaps I do corner quicker than most

cheers

Pete

[plastic orange]

Checked over the car fully today - on ramp and rollers. The only wear we could detect was the ball joints in the upper control arm - and only when weight on the car, and the use of a large pry bar. So new arms ordered from eBay.

Discs and pads seemed fine.

I'll report back.

Pete

[ManicMark]

Checked over the car fully today - on ramp and rollers. The only wear we could detect was the ball joints in the upper control arm - and only when weight on the car, and the use of a large pry bar. So new arms ordered from ebay.

Discs and pads seemed fine.

I'll report back.

Pete

Very close to ordering some of those myself, so will look forward to your report on their quality and fitting.

Hi I bought a pair off eBay a2z parts they have been on for 3000 miles now & are fine easy to fit aswell. Stoped the warped disc feeling you get when brakeing from higher speeds.

[plastic orange]

Super quick delivery - parts arrived today.

Pete

[Alex C Brown]

You sound like me, I have also spent a bit doing my car up, including new front suspension, alloys, full cam belt and spark plug service and all filters, etc. Causing mayhem with finances but she sure drives lovely... I did the alloys because, despite the front suspension change, there was still an oscillation at 40+ mph from the front right tyre (buckled rim).

Have you rotated the wheels front/back to see if the symptoms change? This has to be the cheapest option to see whether the problem is tyre/wheel related or suspension/brakes. If the problem doesn't go away then:

Get the brakes checked out - were the calipers or disks damaged during the tyre change?

Have a proper 4 wheel alignment check done - many places offer "Free" checks - this is different to the standard wheel tracking (!)

Make sure you have the suspension arms checked for obvious bush/ball joint wear (check out YouTube item "LS400 Wheeler Dealers http://www.youtube.com/watch?v=QzMYT22PBeE...feature=related 8 minutes 30 seconds to get an idea of what bad looks like). The lower strut bush is a monster - about 2 inch diameter and very prone to cracking up with age.

I have an assorted collection of arms and bushes from the original suspension that are still well within tolerance if you find anything broken.

[plastic orange]

The whole brake/suspension thing seems to affect quite a few cars. I've replied to pm's asking about the eBay control arms, but won't know for certain if they cure the problem until Tuesday. My car doesn't shake until braking from around 60 - nice and smooth otherwise. I guess the only real solution is to renew everything - first time I've had to contemplate this on any car in nearly 40 years of motoring.

Pete

[plastic orange]

2 new arms fitted today - did it cure the problem? - NO.

I guess I'll have to fit new discs (Blueprint - £181 with pads), but they are well within tolerences. I'm starting to get a bit fed up now.

Pete

[SteveLS400]

2 new arms fitted today - did it cure the problem? - NO.

I guess I'll have to fit new discs (Blueprint - £181 with pads), but they are well within tolerences. I'm starting to get a bit fed up now.

Pete

Please hang in there, it is frustrating, time consuming and costly.

Have I re-read this right? This started after she had new tyres?

I would go back to this point. In the past I have had new tyres and theyve been balanced etc etc but I have had vibration. If I remember correctly, the tyres had a fault, details of which I cant remember. Apart from a bit of time it wont cost to go back and tell em that they need rebalancing due to the problem AND stand with em whilst they stick them on the machine.

That not being the issue/cure, I would have a full digital track done but note if you are thinking of changing any other suspension parts, front or rear, wait and have it done afterwards.

Steve

[plastic orange]

I'm going to swap the wheels from back to front (original position) then see what happens. There is no shake/vibration until I brake from 60mph and over.

I watched the fitter balance the tyres when they were fitted.

Pete

[SteveLS400]

I'm going to swap the wheels from back to front (original position) then see what happens. There is no shake/vibration until I brake from 60mph and over.

I watched the fitter balance the tyres when they were fitted.

Pete

Good Pete.

If it cures it, its definately a duff tyre. for goodness sake keep us up to date.

Steve

[plastic orange]

New discs/pads tomorrow - here's hoping.

Pete

[plastic orange]

Problem solved with new discs/pads. Old ones don't look bad at all - only done around 40k. I'll get them skimmed and keep as spares.

Pete

[Peter L]

Don't know if anybody is interested but got a set of front discs and set of rear discs with Mintex front and rear pads - offers ? I bought these thinking needed changing only to be told that the fluid was low ! Doh ! Would take them back but they want 25% restocking fee as correctly supplied ???