Brake pistons seizing

[Juddian]

Just completed my annual full brake service, comprising of stripping out pads clean up, exercise the pistons in their bores plus lube up and reassembly...my indy bled the brakes out when it went in for MOT a few weeks ago and the brakes are superb.

However, very glad i did the service because on both sides front one of the 4 pistons was semi seized, requiring fair brake pedal pressure with engine running to free those stuck pistons, i've now lubed them by feeding the correct red brake grease inside the dust covers and putting them through the extent of their travel in the bores several times, i shall repeat that before next winter.

Why i'm putting this thread up, it was the same piston seizing each side, namely the lower piston on the inside of the caliper, engine side, obviously this is the one that gets the salty water the most, take note chaps and check yours are all free moving before it costs you a pair of calipers.
The other pistons were free moving as were the rears.

 

[TonyP]

As I was reading your post, I was saying to myself must be lower inside on both calipers.....

Whats your mileage? Unfortunately these do need to be kept clean and serviced regularly. I replaced both my calipers for refurb ones, before that I replaced a few of the pistons. My 120 I coming up for 15years old and 135k miles....

 

[Juddian]

2005, 108k miles.
All original calipers, this is the first time i've found any partial brake seizures on the motor.
Gave the areas accessible in the wheelarches a good spraying with ACF50 whilst there, tomorrow if my back is up to it i'll do the underbelly.

 

[goodoldboy]

changing the brake fluid every 4 years is recommended also as it is hygroscopic & iv'e often thought that this could contribute to pistons seizing.

 

[AndycruiserguyLomas]

When I bought mine 2 years ago I went through the brakes on mine. i checked the piston movement while the pads were out and found the same thing, one piston on each front caliper semi seized . All stripped down ( pistons pressed out with the foot brake). The pistons were all ok except the two semi seized ones which I replaced with 2 good 80 series ones. The important thing is to de rust the "land" between the seal and the top with a rotary flap wheel ( while the seal is removed) and I usually coat this with rubber grease and re assemble. Cleanliness is everything though and compressed air and brake cleaner helps no end.
All pistons free and new pads and discs all round and the brakes are good for years. The rear calipers I overhauled with a kit from Bigg Red.

Mine was 13 years old with 130k. the discs weren't too bad TBF but it is moisture getting past the dust seal and the "land" rusting which nips the piston. I've overhauled loads of calipers from Lotus to Chevy and never come across one which was actually rusty behind the piston.

 

[TonyP]

In my opinion the Toyota caliper design is somehow crap/flawed. Was the same on the 90

 

[AndycruiserguyLomas]

In my opinion the Toyota caliper design is somehow crap/flawed. Was the same on the 90

100,, 80,70, 60 and 40, Hilux's too.

 

[MarkW]

You can fit the 150 brakes to eliminate some of the 120 brake issues, very popular with the GX470 guys in the states

 

[Deleted member 13129]

If your front calipers are partly seized you may not notice it coz the rear brakes work much harder to compensate , to the point of the rear pads only lasting 7000 miles from fitting new rear pads , I only noticed my front calipers were partly seized when I had a mot . But I fitted 2 new calipers that I got from a company called KVA Distributors the cost was £135 for the pair and brand new not recon , when I fitted them I fitted the shims in the wrong order so the pads were squeakily until I fitted them right way round , and I fitted 2 new rear calipers from the same company cost for them was £118 for the pair same new and not recon , thats when I noticed the rear pads had only lasted 7k miles when I was swapping the old rear calipers over to the KVA ones , I know that sounds cheap but the KVA calipers are really top quality parts , that was about two years ago and the calipers have been perfect ever since since , I think Higgy got some for his 120 when he had one as well after I told him about them .

 

[Chris]

I have to agree with previous comments. I have been working on my own cars since I was 17. I haven't had these brake problems with any other make than Toyota. OK I hated the other cars, but the brakes never seemed to sieze up like these. My Hilux just passed 60k last month and needed new discs - they were beyond machining and I ended up putting new calipers on. I could not shift one of the pistons at all. I was in danger of bursting a seal somewhere. I'll refurb them on the bench at some point.

I have always used red rubber grease until recently. This last set I built for the 80 I assembled them using brake fluid instead. I am not completely sure that the red grease isn't part of the problem. Yes it's good for some parts and it doesn't attack rubber, but when I go in after some time for a rebuild, there's typically no trace of it. Just muck and dirt. The Hilux hadn't had a good brake work out to this point becasue it was still on the original pads.

I shall see next time I go in for a check.

 

[Juddian]

Seems a common theme, handy info that replacement calipers arn't silly expensive, but if they do need refurbing next year i might send them to Bigg Red and let them do the job.

I think its a Japanese issue here generally not confined just to Toyota, we had a Mitsubishi Outlander for a short while, competent enough motor but never really endeared itself, and that had a seized rear caliper that needed replacing, very difficult to find pattern parts for Mitsi and you'd need deep pockets to ever venture anywher near the main dealer's parts dept.

We have a 2008 Forester as well as the Toyota, that too gets annual brake servicing, similar drum inside disc design at the back, trouble free braking system albiet with single piston calipers all round so whilst relying on free moving sliders you'd know pdq if there was a seizing issue as brake imbalance would be obvious, with those 4 piston jobbies on the Toyota those lower inner pistons could be seized for a long time before you'd really notice an issue.

Daughter is a Honda Civic fiend, they too are prone to caliper issues, especially the rears which incorporate the parking brake on the pads by an internal adjuster within the caliper, a troublesome design once the salt's done its work.

 

[Deleted member 13129]

Replacement calipers from toyota are silly expensive , I was going to recon my own calipers and bought a recon kit 8 pistons , seals , outer rubber boots and spring clips that hold them on etc and cost me just under £100 from Brakes International in Rochdale , very nice people they forgot to send the rubber/silicone grease with them and when I phoned them they sent me the grease and gave me a full refund and told me to have the whole kit on them as a sorry for them not putting the grease sachets in the kit , when I got the seized pistons out I found the cylinder bores were corroded quite bad so rebuilding them was not possible , they must have been seized a while , and for just over £35 more I found a new pair of calipers of super quality from KVA Distributors in Ruislip Middx , they look good as well as they still look brand new after two years as if they have just been painted and lacquered no service rust on them at all , so good that I bought a pair of rear rear calipers for £118 as well so just over £250 for 4 calipers would have even been cheaper if I bought them all at the same time , at Toyota they would have set me back nearly 2 thousand pounds for both front and rears and to have had to change them again in a few years coz they would have seized up again , but more important they work really well at all speeds and with super smooth even braking .

 

[Juddian]

KVA distributors is etched i my memory, much obliged to me learned friend, it would probably cost the same to get my existing calipers refurbed should they need it, will decide later on in the year when i check again and see how those inner lower pistons are doing.

Just out of interest TonyCY did you bleed the new calipers traditionally or did you use techstream and go through the system as required, i assume techstream has this facility? if you used traditional method did you have the engine and therefore the pressure pump running?

PS, told TonyP a lie earlier, its done 110k now not 108, not noticed the mileage cos the Mrs and i have been using each other's cars more, her Forester is running LPG so makes my work commutes much cheaper.

 

[Deleted member 13129]

I bled the brakes traditionally using a one man bleeding pipe but got the wife to press peddle on/off about a dozen times with ignition light on coz with the ignition light off I pumped the peddle about 40 times before I took off the calipers to let the pressure out coz I did not know how much pressure was built up with the electric motor the brakes use just in case brake fluid came out under pressure when I undid the pipe to the caliper , as it was it just dripped out . keep an eye on the brake fluid tank dont let it run below one third full .

 

[Juddian]

Much obliged for that, i was a little worried that traditional bleeding might not be suitable for these motors with the electric pressure pump, but that's proabably more of an issue if the ABS unit gets air inside, or the master cylinder/pump unit has to come off.