[OldRav4]

Hi everyone,

2000 Rav4.1, 4 door, 4WD, ABS..? (there's an ABS light on the dash...)

Just replaced both of the front brake calipers and pads. Proper caliper bleeding process was followed (furthest from the master cylinder first, to the closest). Did this twice. Fluid level on the master cylinder reservoir was never below the minimum mark. Brake pedal is now really soft, but still have brakes. Where to go from here?

I have read about the ABS module needing to be bled as well? How do I do that? Where is the ABS module in our engine bay?

Any help would be thanked with a 6 pack

 

[Ken Allistone]

Open the hood, standing facing the car, the abs module is bolted to the inner wing and in front of the suspension turret on the left hand side, to the left of the steering reservoir. You will see all the brake pipes connected to it.
I havnt heard anything about bleeding it, I'm sure there's no valve on it for this either, I've changed all my brake fluid without any problems, and from what youve said I wouldn't expect the problems your experiencing.
When you did the calipers, did you clamp the flexible brake pipes to stop the fluid leaking and air getting in?
Some cars, not mine and not necessarily your RAV (or any RAV) have a pressure compensating valve in the brake line between the front and back, these can make bleeding harder, as I said, I don't think you have one but it's worth a look.
Maybe US cars are different?
When you installed the calipers, did you prime them first, I know it's messy but did you fill them with fluid before you connected the pipes, I know this will sound crazy to a lot of people but there could be an air pocket in there. I've had this problem before on clutch slave cylinders.
Otherwise all I can suggest is check the hoses are all good, no swelling, check there's no leaks and bleed again, slowly, try not to push the pedal all the way to the floor and nip the bleed nipple up at the end of every down stroke. Good luck.

 

[OldRav4]

Hi Ken,

Thanks for your reply.

When replacing the calipers, I did not clamp the brake hoses. Instead, I loosened the banjo bolt before taking the caliper and caliper bracket off then installed the new caliper & bracket. I then very quickly disconnected the old banjo bolt and connected it to the new caliper. Once that was tight enough (25 ft. lbs), I loosened the bleeder screw until I saw fluid coming out, then tightened it. This was done to both front calipers.

Also, when bleeding all 4 brakes I used a 1/4 inner diameter clear hose and a zip tie just in case air was getting into the little cracks between the hose and the bleeder screw. I had a helper press on the brakes in the car slowly after I opened the bleeder screws and had him lift the pedal back up once I closed it. I did at least 10 pumps on each corner to make sure the fluid was free of rust, air bubbles, and was clear. I thought I did more than enough to pump old fluid and air bubbles out.

All brake hoses seem to be in good shape. No leaks, no swelling. Master cylinder isn't leaking either. I can't find any fluid on or around the master cylinder.

Cheers,
Johnny

 

[Gunner]

Hi Oldrav4

If your helper wasn't experienced at bleeding brakes he may have pushed the pedal in too far and possibly turned or damaged the seals on the master cylinder which can give the effect you explain. If this has occurred the pedal will drop slowly to the floor when you hold pressure on it. I always like to use a pneumatic or one man bleeder as some abs systems can be a pain in the *** to bleed and I usually have no help.

 

[Ken Allistone]

Johnny,
What you did sounds ok, normally you wouldn't expect to have a problem, clamping the hose makes life easier and less messy. Priming the caliper helps a little too but many people have done what you did and had no problem.
Gunner is right to suggest you don't press all they way to the floor, just in case the seal on the piston does what he said, maybe yours has, or maybe the lip has been damaged, there's usually two seals on the piston, depends if the circuits are front and back or diagonal. Maybe you are only getting the benefit of one?.
Did you determine if you have abs?

 

[OldRav4]

Thank you for the responses.

I have asked my helper. He did indeed press the pedal all the way to the floor when I opened the bleeder valve. What you two said might be correct. Maybe a seal has been broken in the master cylinder.

As for ABS, I've tried slamming the brakes for a 60-0mph. I can't say for sure if the wheels locked up because I didn't hear any squealing of the tires, but I did feel a minimal pulsation through the brake pedal.

Also looked under the hood for the ABS module. It is indeed there, sandwiched between the windshield washer reservoir and the passenger front strut mount.

Brake pedal is rock hard when the car is off. It only sinks when it's on. Could that be the brake booster?

 

[Ken Allistone]

Yes, the booster looses its vacuum if you pump it a couple of times and the pedal will feel hard. Don't be hard on your helper, if it is the master cylinder, it's probably due to age as much as anything they did, next time place something like a block of wood under the pedal so it wont go all the way down.

 

[OldRav4]

Block of wood noted down. Now onto the next project of replacing a master cylinder.. Any tips or tricks?

If it's as simple as some youtube videos.. Unbolt, bolt on, bleed cylinder, bleed calipers again?

 

[thetyrant]

Could just be air still in the system and further bleeding required, try tapping caliper when bleeding in case there is an air bubble stuck inside which ive seen before, also i must ask you say you replaced the pads but did you also replace the discs ?

If not then the softness could just be down to pads not fully contacting the worn discs, this gives a soft pedal as the pad has to try and tip to contact rest of disc and until pads wear the shape of the disc it will feel mushy, even new discs and pads can give this problem and i see it a lot when people replace brakes complaining of softness of pedal initally.

Getting some more miles on them will sort it if that is the problem but of course you need to be sure everything else is good first to be safe.

Damaging seals in master cylinder by using full travel used to be a big problem years ago as mentioned above, but i find its rare nowadays but is one to bear in mind i guess if nothing else comes to light, to me i would like to be sure the master cylinder can handle full travel should the need arrise, better it happens when bleeding the brakes than in an emergency situation.

More often soft pedal problems are mis-timing of pedal pusher and bleed nipple operator that sucks some air back in, i use one those cheap one-man bleed pipes with a oneway valve on the end mostly so i can do it myself, but even when i do have an assistant i still use it just in case they let pedal up before i close nipple and give instruction!.

Ian

 

[OldRav4]

I did not replace the discs/rotors. I inspected them before ordering parts, they were in good shape with no signs of warp. Plus, the old pads were flat.

I made it absolutely clear to my assistant that he was not to let the pedal up until I closed the nipple and said "up" so I don't think that's the culprit here.

I can try tapping on the caliper to see if there are still any air bubbles stuck in the caliper.

Note: Brakes still function. I didn't die on my way to work today

 

[thetyrant]

OK no worries, it could just need some more miles on it all to get it the pads and rotors perfectly bedded as even though things look flat it can take a while to wear exactly to shape and even the slightest pad tip will give a nasty pedal, mind you it should be obvious looking at rotors if pads are making full contact, check the inner and outer faces for nice even contact over whole area, if its not then give them a good workout to bed in further.

Other than that my advise would be give it another bleed and calipers a tap in the process in case there is air trapped in them, also maybe let it gravity bleed a little which is what i usually do when changing calipers, by this i mean once ive quickly swapped calipers over and pipes connected i then crack open bleed nipple and with cap off the res under bonnet and and wait for fluid to slowly fill the calipers and come out nipple, only then do i get on the pedal to pump some new fluid through, doing it with gravity helps prevent air trapped in calipers.

Glad your still alive anyhows i need to get onto overhauling my Ravs brakes as they are shocking!...was going to wait until after winter but i may end up crashing into something if i dont do something sooner!, it doesnt help that my other car has awesome brakes so i need to recalibrate my braking when i jump in the Rav.

 

[OldRav4]

I'll put some more miles on it and see if that helps. I doubt it though, my old factory brakes did the same thing. This is really why I replaced the calipers, because I couldn't open the bleeder valves to bleed the front brakes.

That's actually what I did when replacing the calipers. I opened the bleeders until fluid came out then I bled the brakes using the pump method.

I actually thought of replacing the rear drum brakes into disc brakes and fronts with dual piston calipers but couldn't find any kits. That would substantially improve the braking on our ravs!

Btw, I replaced the calipers in 40F weather. You shouldn't wait until the winter is over haha.

 

[thetyrant]

Hmm ok didnt know you had the problem before, could be be the booster or master cylinder then, have you had rear drums apart to check all is well in there ?

40f would be nice... its 20f here at moment ....i so need to build a garage!

 

[OldRav4]

Yeah I forgot to mention it. I thought the reason for soft brakes were air in the system, but when that didn't work I was really confused.

Drums are fine. Not in excellent condition but they're rear brakes so they don't make much of a difference in braking anyway.

20F is fine! Wear some gloves, tuck in your undershirt, and wear some layers. You'll be alright
I actually have a garage but I chose to do it in the street because I didn't want to clean up the fluids that'd be leaking on my floor hahaha

Update: Master cylinder ordered via rockauto. Sweet prices as always.

 

[thetyrant]

My Rav's brakes are pretty spongy at least compared to my bmw, but i put that down well worn pads, rotors and old fluid as well which doesnt look like it been changed in some time! previous owners have not done much with brakes for awhile from what i can see!

Drums wise i was more meaning the adjustment and cylinders etc all being ok, if the adjustment wasnt good (which i presume is automatic on these but ive not looked yet) then it could make pedal a little spongy, also a bleed of rear brakes if you havent already and they are not rusted up to get new fluid through would be benefical to rule out any air or bad fluid in the system.

Hopefully your new master cylinder with another good bleed and some more mileage will sort it.

Ian

 

[Ken Allistone]

The rear shoes are self adjusting, surprisingly they seem to be reliable too, I would pull back the rubber covers on the wheel cylinders though, just make sure they are not leaking, the rubbers are a nice fit, it's conceivable there's fluid being contained inside.

 

[OldRav4]

My Rav's brakes are pretty spongy at least compared to my bmw

But does your BMW have an oil dipstick? :egad:

I bled the rear brakes as well. Fresh clear fluid coming out of the bleeders. Cylinder doesn't appear to be leaking at all. Bone dry inside and outside of the drum.

Master cylinder will be delivered tomorrow. Hopefully the install will go flawless.

Thank you all for the responses. Seriously.

 

[Ken Allistone]

Hope it goes well and solves the problem, let us know, we're all glad to help.

 

[thetyrant]

But does your BMW have an oil dipstick? :egad:

I bled the rear brakes as well. Fresh clear fluid coming out of the bleeders. Cylinder doesn't appear to be leaking at all. Bone dry inside and outside of the drum.

Master cylinder will be delivered tomorrow. Hopefully the install will go flawless.

Thank you all for the responses. Seriously.

Haha don't even get me started on that lack of oil dipstick on the beemer! :laugh


Looking forward to how the master cylinder swap goes, fingers crossed it sorts it.


Ian

 

[OldRav4]

Still too cold outside (10F) to install.. :roll: :doh: :? :x onder:

Btw, I would need to bleed all 4 wheels again after installing the MC, right?