Brake Pedal Making Knocking Sound

[alidot]

Hi Everyone

I bought a 1998 Rav 4 last week, with only 49K on the clock, everything is great apart from when I brake I feel a knocking/juddering in the brake pedal, this doesn't happen all the time which is very strange.

I've just had the brakes/rotors and ABS checked and all are fine, the mechanics couldn't figure it out but said it was safe as nothing was loose, etc.

Does anyone have any experience of this and what could be the cause?

Many thanks for any advice.

Alison

[daveh_rav4]

Hi Alison...

Well, if your mechanic has checked the pads and discs for run out/corrosioin and the wheel nuts are secure etc. Only things I can think of is a foreign object trapped/floating between a disc backplate and the disc! I would certainly re-check the wheel nuts again... as they secure the discs to the hubs. The only other thing I can think of is a badly balanced wheel... this may 'wobble' at certain speed sending vibrations through the brake pedal... but you would certainly feel this through the steering wheel as well! Is it speed related?

Ian (Bothy) our 4.1 expert should be around later... he may have some other ideas you can try.

DaveH

Hi Everyone

I bought a 1998 Rav 4 last week, with only 49K on the clock, everything is great apart from when I brake I feel a knocking/juddering in the brake pedal, this doesn't happen all the time which is very strange.

I've just had the brakes/rotors and ABS checked and all are fine, the mechanics couldn't figure it out but said it was safe as nothing was loose, etc.

Does anyone have any experience of this and what could be the cause?

Many thanks for any advice.

Alison

[cheetah1]

Either the ABS engages without reason, the discs are warped or damaged, loose lugnuts, possibly bad tires or maybe a bad bearing. Or as stated above, somthing loose in the brake area..

[alidot]

Thanks for your replies guys.

I don't feel it in the steering wheel - only in the brake pedal and it makes a knocking sound from the front end, it seems to do it randomly at different speeds, fast or slow or it won't do it at all.

It's a strange one :) I'll go to another garage for a second opinion , but thanks for any other suggestions.

Alison

[jedi134]

Is it an ABS type of feeling? like a vibration through the pedal?

[mrbilly]

first is the knocking sound only when braking or other times like going over bumps

my thinking at the mo is:

1. non toyota brake pads which are only slightly smaller which cause a knock. sometimes you can tell this by reversing from cold and you hear a little metallic clunk when stopping which is the pad moving in the caliper.

2. wheel bearing or cv joint look for grease round the boots.

3. snapped/missing tooth on abs exciter ring causing abs to kick in everytime the brakes are applied (how did mech check abs).

4. possibility of air trapped in abs pump. try bleeding

better detailed info might help also some of these ideas might

[bothwell_buyer]

Hi Alison and welcome to both the forum and to the world of exciting driving. The first version RAv - which we call the 4.1 was in my opinion well made and fairly indestructible.

I have had problems with the front brakes on 1 of my RAVs (I have 2 1994 3 door RAVs). We traced it down to a sticking caliper/caliper piston, which resulted in the pads overheating and then leaving a deposit of the pad material stuck to the disc. this is the most common reason for brakes juddering. Its basically that the disc has a 'bump' of residual braking material sticking to it. A light skim can get rid of it if the discs are not too worn. Sometimes you can tell by looking at the colour and wear on the disc face - uneven wear or dark patches can indicate a problem. The judder behaves differently depending on what speed you are doing.

Other things - wheel balance.

The mileage is not large but the age of the car could indicate possible suspension bush wear/deterioration (see ma spelling - jist gets better and better). A worn suspension mounting bush could cause a knock.

When was the car last MOT'd?

If you are braking gently then the judder could be worse if its the discs that are contaminated.

When it comes down to discs, there are many types on the market well cheaper than Mr T but just as good. The T pads are good though. get a 2nd opinion. If its found that the discs have got pad material (often called a warped disc) then there s reason for it happening and thats normally the calipers needing cleaned and the movement checked/cleaned.

Dunno where in the UK you are but sometimes another RAV driver can give a good opinion...anchorman here is great on this stuff when he's not away driving trains - speaking of which I am travelling to London on Monday by train, depending on snow on the line; cattle on the level-crossing; driver turning up on time; and Sunday track repairs getting fixed......

[igormus]

Hi Everyone

I bought a 1998 Rav 4 last week, with only 49K on the clock, everything is great apart from when I brake I feel a knocking/juddering in the brake pedal, this doesn't happen all the time which is very strange.

I've just had the brakes/rotors and ABS checked and all are fine, the mechanics couldn't figure it out but said it was safe as nothing was loose, etc.

Does anyone have any experience of this and what could be the cause?

Many thanks for any advice.

Alison

hi mate

have you washed yr car recently????? may be a strong water jet could sharply have discs cooled down resulting their curving etc. this sometimes happened. conside this, as well

Cheers/Igor

[alidot]

Hi everyone

Many thanks for all your replies.

The car was MOT'd in December 09 and serviced in Dec 09 too.

I took it to Kwik fit yesterday who did the free brake check, they took the front wheels off and checked the rotors, they said the brakes and rotors were fine, they said it could be the ABS, they sprayed air (if that makes sense) to see if something had lodged anywhere, they took it out for a drive and still felt the brake pedal knocking, they had it up on the ramp, checked the suspension, etc. they said nothing is loose and it is safe to drive but they weren't sure what the problem was!

I'll be taking it to my usual garage to see what they can come up with and will hopefully be able to post the solution. :)

Thanks again!

[alidot]

Hi

I just thought I'd post an update on my brake pedal problem.

I took it to National tyres for a free break check (I wouldn't normally go there) they said I needed new pads, discs and caliper £451!!

Anyway I took it to my usual garage and it turned out to be the cv joint and a new ABS ring, which cost £97 - so now the clicking/knocking has gone away.

Phew, thanks for all your advice.

[mrbilly]

good to hear you got it sorted but i just wanted to brag and say that it was two of the things in my earlier post on this topic

[alidot]

So you did!! Well done mrbilly i'm so glad it's fixed:thumbsup: