2002 Rav 4 Spongy Brakes

[Dave2000]

The brakes on my Rav 4 have recently became very spongy. There is no fluid loss, the brake pedal will firm up when pumped with no engine running, then as expected goes down with engine running, but seems to go too far and will not firm up when pumped. I've tried beeding ( 2 man method) and much air has been extracted but I cannot get it all out. After a good litre of DOT4 the situation is as follows at every wheel - at each pump the extracted fluid starts nice and clear but a stream of bubbles appears towards the bottom of the pedal stroke. I tried at least a further 10 pumps on each wheel but cannot improve the situation. As every wheel is affected I assume its not the calipers. Is the master cylinder likely ?

Can anyone help / explain, please advise

The only recent work on the brakes is new pads a good 8 months ago and they all seem fine.

Dave

[gar]

The brakes on my Rav 4 have recently became very spongy. There is no fluid loss, the brake pedal will firm up when pumped with no engine running, then as expected goes down with engine running, but seems to go too far and will not firm up when pumped. I've tried beeding ( 2 man method) and much air has been extracted but I cannot get it all out. After a good litre of DOT4 the situation is as follows at every wheel - at each pump the extracted fluid starts nice and clear but a stream of bubbles appears towards the bottom of the pedal stroke. I tried at least a further 10 pumps on each wheel but cannot improve the situation. As every wheel is affected I assume its not the calipers. Is the master cylinder likely ?

Can anyone help / explain, please advise

The only recent work on the brakes is new pads a good 8 months ago and they all seem fine.

Dave

Sounds like you either have a leek or you are not following the bleeding sequence correctly, as you normally have to do it a specific way round, according to the owners manual.

To be honest, I would go to Toyota and get them to do it properly, it should be fairly strait forward if it is just a change of fluid. I think it costs around £60 to £80. Worth it for peace of mind.

[Bodgit-fixit-run]

Have you checked for leaks at the master cylinder? Look inside the car as well as some master cylinders leak down the push rod and drip into the drivers foot well.

Invest in a pressurized bleeding kit as this will work without having to keep operating the pedal. I suspect the master cylinder.

[Dave2000]

Have you checked for leaks at the master cylinder? Look inside the car as well as some master cylinders leak down the push rod and drip into the drivers foot well.

Invest in a pressurized bleeding kit as this will work without having to keep operating the pedal. I suspect the master cylinder.

Pressed reply button by mistake, see repeat below

[Dave2000]

Have you checked for leaks at the master cylinder? Look inside the car as well as some master cylinders leak down the push rod and drip into the drivers foot well.

Invest in a pressurized bleeding kit as this will work without having to keep operating the pedal. I suspect the master cylinder.

There are no signs of fluid leak and would agree the master cylinder is the favorite. Is there a way I can confirm that air is being drawn into the master cylinder before I go ahead with a replacement. I've bled enough cars over the years to convince me it's not just a "bleeding" problem.

[bothwell_buyer]

Interesting - Highlandjock has a problem with his clutch that seems might be hydraulics related. I think he's going to replace the cylinders and using a pressurised method to clear fluid out.

[anchorman]

I missed this one somehow!!!

Just let me understand this. With the engine switched off the pedal is rock hard and if you keep your foot hard on the pedal it doesn't "creep".

If this is the case - stop worrying they all do it. You can press my 4.3 (and any other) nearly to the floor with the engine running. It is the system responding to your request for more pressure.

If the system is properly bled through and you open a nipple you will find it runs free of bubbles by gravity. This is OK.

[Dave2000]

I missed this one somehow!!!

Just let me understand this. With the engine switched off the pedal is rock hard and if you keep your foot hard on the pedal it doesn't "creep".

If this is the case - stop worrying they all do it. You can press my 4.3 (and any other) nearly to the floor with the engine running. It is the system responding to your request for more pressure.

If the system is properly bled through and you open a nipple you will find it runs free of bubbles by gravity. This is OK.

Thanks for the comments. Perhaps I am worrying too much. The pedal is near hard with engine off so there must still be a little air in the system. Yes it doesn't creep but the pedal is far more spongy than any other car I've driven (engine running). What bothers me is during the latter stages of bleeding (2 man), the existance of a small fine stream of bubbles towards the end of each pedal stroke at EVERY wheel. Possible a coincidence but suggests to me that the system is sucking in a little air at the same point in each pedal stroke. I'm planning to re-bleed the system over the next few days (pressure or suction method) and see how it goes.

[mike xt-r]

Hi, the bubbles could be from a poorly fitting bleed pipe, or from opening the bleed nipple too much and sucking in air when you release the brake pedal via the threads, and pumping it out when you repress the pedal. Check closely that its not a pad or calliper causing your spongy pedal feeling, a pad/calliper could be stuck and causing the piston to travel futher as the pad/calliper flexes, something that would not show up when the engines off (no servo assistance= less pressure applied to the hydrolics) so you will have a good pedal. Hope this is of some help. Mike

[Dave2000]

Hi, the bubbles could be from a poorly fitting bleed pipe, or from opening the bleed nipple too much and sucking in air when you release the brake pedal, and pumping it out when you repress the pedal. Check closely that its not a pad or calliper causing your spongy pedal feeling, a pad/calliper could be stuck and causing the piston to travel futher as the pad/calliper flexes, something that would not show up when the engines off (no servo assistance= less pressure applied to the hydrolics) so you will have a good pedal. Hope this is of some help. Mike

Thanks for your input. I'm sure all the bleeds were closed before releasing the pedal. I'll recheck all the pads / calipers when I do the rebleed. If there was a problem on the front I would have expected some feel thru the steering wheel but maybe not the rear.

[trbj]

May I suggest that you take all four front brakepads out and check once again that they are all at their right location, - this bearing in mind that there are differences between the inner and the outer pads, however not more than that it is possible to get them in the wrong position by applying some force.

First time I changed mine I managed to get it wrong with a spongy, and even sinking, brakepedal as a result. Suspected the masterpump immediately, but that was not the answer. God the pads fitted where they should fit and the problem was gone!

[trbj]

Hi, - did you ever get to the bottom of it? Or did the pedal eventually go to the bottom....!