Shaking when braking going down hill

[moomoo Lurker Find all posts View Profile Close moomoo]

I drive 2010 150 and have just started to encounter some shaking when applying brakes going downhill. I am only really feathering the brakes and it is noticed more in the steering wheel.

I have had the brakes checked by a 4wd place last week ie rotors etc and said all is good. Had my brother in law look as well one of his mates who use to be a mechanic and they said brakes all good but did comment on the overgreasing of tailshaft (previous toyota service).

When discussing with mechanic from 4wd place, he believes coming from the rear of the car. He did comment that the psi of my tyres was a bit high at 40 on ATR's and have subsequently dropped to 36.

Wheels have had an alignment, which I thought might be part of the case initially but wheels not balanced at this stage.

I have googled the issue and found a few things on earlier prado's being cracked engine mounts, shafts needing rebalancing\replacing etc

any suggestions would be appreciated but all in all a good car.

Paul

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

OK if it only shakes when you brake then it is the brakes or wheel bearings and nothing else. If the steering wheel shudders then it is the front if you feel it through the seat (of your pants) then it is the rear. I guess it is possible it is a badly worn tyre but I would expect that all the time and definately under acceleration as well as braking.

Only way to tell if the rear discs are warped is to drop them off. You can try to put the car on stands and use a dial gauge but you may not get a decent reading. How many ks and have you been towing heavy trailers and doing a lot of braking?

For wheel bearings jack the car up and put it on a stand and then try to move the wheel by hand or using a breaker bar. If it goes clunk then it is a bearing.

I believe you will find it is warped rear discs, quite a few of us have had to do those. Cannot remember anyone changing a wheel bearing. If you are doing the discs yourself remember to back the hand brake off and take some tension off the parking brake shoes so you don't catch the springs and retainers taking the rear discs off. There is a thread in the 120 section how to do this and I guess the 150 is fundamentally the same.

[Bear63 Senior Member Find all posts View Profile Close Bear63]

Definitely disc run out , the only way to check the amount is with a dial gauge , you wont see be able to see it with your eye , how many k's on the clock?

[Nadsy Junior Member Find all posts View Profile Close Nadsy]

I just recently noticed the same thing. Down hill only, and under moderate braking from an 80 to a 60 zone. Same effect on old tyres as with new tyres. Same effect at 36 psi vs 45 psi (which was what it was at after a service ;-/). Asked them to check it out... but all was good apparently.

Spoke to someone I know personally about it, and they said it was probably the ABS, and the downhill breaking making it anticipate ahead of time (I don't have a technical background, so this could be an incorrect description)? Anyway, does the pedal kick back?

[moomoo Lurker Find all posts View Profile Close moomoo]

Thanks for replies. Answers to questions above

- no towing with car
- car has done approx 36500K
- will ask for disc;s to be checked with dial guage

Nadsy - looked for the kick back in the pedal this arvo but did not notice but will keep in mind over the next few days

[Bear63 Senior Member Find all posts View Profile Close Bear63]

Its not the ABS Nadsy , if you want to know how the ABS feels take the car onto a gravel road at low speed and hit the brakes as hard as you can , you will feel the vibration through the brake pedal and dont worry you wont break anything
The shudder being described under light braking is disc runout

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

Sounds simple. Common issue in many vehicles these days.
It's when u brake! and It's at the front, as you get it at the steering wheel, right?
It's D.T.V (disc thickness variation) once you have it, in service it just gets worse.
Machine the rotors on car by a good Machiner.