Brake Caliper Rebuild (3 Viewers)

[sunrk]

Here's a tip for getting the pistons out of the caliper, works really well, especially if you're pistons are really stuck and rusty. No amount of air pressure will get a stuck piston out, it can be a real fight. BTDT...

Before opening any brake lines or draining any fluid out, go around and pull the pins and brake pads out of the calipers (leave the calipers mounted). Then just get in the truck and stomp on the brake pedal. The hydraulic pressure will force the pistons out. Stuck or not, they will all come out if you press hard enough. WOrks every time!

I did something similar but had the caliper off the hub, still connected to the brake line, and pit a piece of wood about the same thickness as the disk in between the pistons. One came out so easily that it started leaking fluid straight away. The other three required the careful screwdrivering method.

Craig.

 

[sunrk]

Damn the pistons are not going back in.

Damn it the pistons are not going back in. I've got all the four seal rings in place, with plenty of grease on them and the first piston I'm trying to get back in, but it will not pass through the seal ring. The kit is the right one for the front cals on my 3/92 80 series.

Going to have lunch then come back to it otherwise I'll end up getting frustrated and wrecking it or myself! I don't have a press, or a vice, available, to use for gently applying increasing even force until it goes in.

Craig.

 

[serenity]

Damn it the pistons are not going back in. I've got all the four seal rings in place, with plenty of grease on them and the first piston I'm trying to get back in, but it will not pass through the seal ring. The kit is the right one for the front cals on my 3/92 80 series.

Going to have lunch then come back to it otherwise I'll end up getting frustrated and wrecking it or myself! I don't have a press, or a vice, available, to use for gently applying increasing even force until it goes in.

Craig.

Try twisting the pistons while pushing them in, you shouldn't need to use a vice or ram. Do you still have the caliper split? it's easiest to press in the pistons with it split then bolt the 2 halves back together later.

 

[sunrk]

Try twisting the pistons while pushing them in, you shouldn't need to use a vice or ram. Do you still have the caliper split? it's easiest to press in the pistons with it split then bolt the 2 halves back together later.

I didn't split the caliper body at all. I'd tried twisting the one I'm doing first a little but didn't want to turn it too much. Maybe I'll just have to turn it a lot more and treat it like I'm turning a screw or bolt to get it to pass through the new seal ring.

Craig.

 

[serenity]

Yep that's the way, it will help the seal ride up and over the radius on the back of the piston.

 

[sunrk]

Yep that's the way, it will help the seal ride up and over the radius on the back of the piston.

No good. Tried it with a second piston and the same result. No matter how much force I apply and how much I turn it, it isn't going past the seal ring. I may have no choice but to take the caliper body apart and make sure I don't lose the existing o-ring seals between the two halves.

Craig.

 

[serenity]

Yep that's the easy option. New o-rings are cheap and can be had from your local brake shop or hydraulics store if they need to be replaced.

 

[Ebag333]

Yep that's the easy option. New o-rings are cheap and can be had from your local brake shop or hydraulics store if they need to be replaced.

You sure that's replaceable?

Last I checked it was a formed O-Ring, and unobtanium. FIPG might work in a pinch....

 

[serenity]

You sure that's replaceable?

Last I checked it was a formed O-Ring, and unobtanium. FIPG might work in a pinch....

Yep I have 2 brand new ones in the calipers I my 80. My brake mechanic stocks them. If you go back a few pages in this thread I posted photos and sizes. Looking at the design of the caliper you could replace them with a standard o-ring if necessary.

 

[sunrk]

Yep that's the easy option. New o-rings are cheap and can be had from your local brake shop or hydraulics store if they need to be replaced.

Snookered again - I don't have a 14 mm 1/2" drive socket that will fit properly over the bolt heads without fouling on the caliper body. Tried my regular 6-point one. Don't have a 3/8" drive one available. So I've got it apart using a normal ring spanner however even with the two halves apart, I can't get the pistons in and I've applied as much force as I can while trying to turn a piston. I've got to be doing something wrong...

No $$ until mid-next week so can't get a different seal kit (or even a toyota one) to try out until then. Damn also means I can't get to work after 2 more days since car (Saab) will be out of fuel by then. Nothing worse than having a vehicle unusable because of something simple that is being a PITA to sort out!

I tossed the old set of seals in the bin two days ago. I do still have the original LHF caliper which has worse pistons than the one I'm repairing now and it's totally siezed up.

Craig.

 

[serenity]

Have you tried a spanner? If your having trouble getting enough force on it then bolt the caliper onto the knuckle (did you say you don't have a vice?). You might need to hit the spanner with a hammer to get the bolts loose, even though that's not best practice.

 

[sunrk]

Have you tried a spanner? If your having trouble getting enough force on it then bolt the caliper onto the knuckle (did you say you don't have a vice?). You might need to hit the spanner with a hammer to get the bolts loose, even though that's not best practice.

I just got a bit heavy with it trying to get a piston in by putting a block of wood over it with half the caliper body on a hard surface and giving it a few hammer whacks and all it's done is start pulling bits of rubber off the seal instead of work it's way past it so that's one new seal ruined. I might have to try stretching the seals to get them slightly larger in diameter. Lucky I still have 4 more spares in the kit. Not sure how far they'll flex.

Righto tried stretching a seal before putting it in the bore - that was a little better but what I noticed was that the small area of the piston that had the corrosion along the back circumference seems to be what's digging into the seal and tearing bits off. Wrecked a second seal one trying that idea out. All four pistons have a tiny area of corrosion like the first one.

Note that it's not a genuine Toyota seal kit - it is Japanese made though but I have a suspicion the seal rings are too small (just), as all the guides say the pistons should be easy to push in past the new seals. I may end up having to get the other LHF caliper apart to get at the pistons and see if they are going to be any better. Otherwise just get four new pistons and maybe a genuine Toyota seal kit. None of that can happen until at least the middle of next week.

Out of time for today as I'm off to work in an hour. Might have another crack at it tomorrow. Still have three good spare seals left.

Craig.

 

[serenity]

Just curious how far are the seals protruding out into the bores of the caliper. And what condition are the pistons in? Are you able to post pictures?

 

[sunrk]

Just curious how far are the seals protruding out into the bores of the caliper. And what condition are the pistons in? Are you able to post pictures?

Pistons are excellent apart from those small areas of corrosion around their rear circumference. They polished up superbly well despite the bits of corrosion which I did do quite a bit with using a fine file to try and remove much of the jaggedness - clearly it wasn't enough.

The new seals stick out quite noticably from the slots inside the bores - between 1.5 and 2 mm mostly from the bore face.

I've rescued the old seals from my bin-bag - lucky for me I didn't get rid of the next bag of rubbish yesterday. Might have to re-use them. The seal-rings I removed (they're not damaged) are a good 4 mm or so bigger in diameter than the new ones. The old outer boots are ok but one did have a small tear that I recall.

I do have pics of the pistons, bores, etc. but need to upload them somewhere once I figure out where I have upload quota left - may have to wait until next month to upload them to my 23 acct.

Craig.

 

[serenity]

That right there is your issue! Looks like you got given the wrong Seal kit. Seals should sit almost flush with the bore.

 

[serenity]

Ok so here is what the bore and the seal should look like, this is a 60 series caliper but the 80 and 60 are same design anyway.

 

[sunrk]

Thanks, yeah I reckon the seals are wrong. Got a couple of days off work now after a 9.5 hr shift last night so I'll given the pistons another polish up with silvo, clean up the two caliper halves better than they were before (can't fix the bore corrosion pitting though) and have a go at restoring it to working order using the seals I removed which have no damage at all.

I think most of the sticking was due to the pistons having a layer of black muck on them, combined with the amount of suspended solids in the brake fluid at the bottom of each indiviual bore.

Got enough brake fluid to bleed and top the system up once until next payday once I create a functional caliper from the two LHS ones I've got here.

Craig.

 

[TrickyT]

It's a sure sign of the positive impact that "collective group knowledge" has when you can find an old thread packed full of useful information like this one has. Not only did slomo do a great job with his initial posts and pictures, but KLF's tip for getting pistons out of calipers was worth its weight in gold. My only contribution is bumping an old thread back to the top of the list and to say how great a forum like 'mud is.

 

[gregnash]

It's a sure sign of the positive impact that "collective group knowledge" has when you can find an old thread packed full of useful information like this one has. Not only did slomo do a great job with his initial posts and pictures, but KLF's tip for getting pistons out of calipers was worth its weight in gold. My only contribution is bumping an old thread back to the top of the list and to say how great a forum like 'mud is.

Agreed, I have been planning to do this for a couple weeks now and been doing my due diligence in reading. This thread (and a similar one on Pirate4x4) has been immensely helpful. I am debating on whether I want to crack the caliper in half to pull the pistons or just leave it intact and use some of the methods the guys have talked about.

 

[93yotasr5]

Here's a tip for getting the pistons out of the caliper, works really well, especially if you're pistons are really stuck and rusty. No amount of air pressure will get a stuck piston out, it can be a real fight. BTDT...

Before opening any brake lines or draining any fluid out, go around and pull the pins and brake pads out of the calipers (leave the calipers mounted). Then just get in the truck and stomp on the brake pedal. The hydraulic pressure will force the pistons out. Stuck or not, they will all come out if you press hard enough. WOrks every time!

GREAt TIP!!!!


wish i knew that before i tried using the CO2 tank. i blew up 2 rubber tips trying to push the other 2 pistons out. I ended up having to re connect the calipers and using the brake pressure to bust em loose.