Brake System Overhaul

[Seth_O]

I'm in the process of a complete brake system overhaul on my '93 FZJ80. I had a near-miss in a panic stop a few months ago and have done a bunch of work on them since then, but they're still not what I would like them to be.

As a part of the overhaul I bought 4 used calipers and am rebuilding them all so I can drop them in and only have my vehicle down for the day I am doing the work.

In doing the work on the front calipers I noticed they appear to be held together with 4 bolts (circled in orange in the pic.) If I pull those bolts will the caliper open up along the seam and allow me access to clean/service the inside? Also - will it harm the calipers at all if I hot tank them after stripping them down? I'd love to hot tank and then powder coat or plasti-dip them or put on some kind of solid coating.

 

[bigCatdiesel]

I'm in the process of a complete brake system overhaul on my '93 FZJ80. I had a near-miss in a panic stop a few months ago and have done a bunch of work on them since then, but they're still not what I would like them to be.

As a part of the overhaul I bought 4 used calipers and am rebuilding them all so I can drop them in and only have my vehicle down for the day I am doing the work.

In doing the work on the front calipers I noticed they appear to be held together with 4 bolts (circled in orange in the pic.) If I pull those bolts will the caliper open up along the seam and allow me access to clean/service the inside? Also - will it harm the calipers at all if I hot tank them after stripping them down? I'd love to hot tank and then powder coat or plasti-dip them or put on some kind of solid coating.View attachment 1405383

Search around Mud and you will see different opinions. Toyota doesn't have instructions to split the caliper apart nor is there a replacement seal available from Toyota. However, others say a standard brake shop will have this seal if you split the calipers. One thread had identified the seal dimensions.

This was fresh in my mind from my recent endeavor on caliper rebuilds.

John

 

[LINUS]

I split mine open & just reused that little seal - my driver was to clean out all the spooge that had laid down in the low point & because I'd blown a piston seal & had a hung piston.

The little O-ring isn't a Toyota part, but if you have good calipers & pistons then rebuilding your stuff beats a nameless/faceless rebuild from the lowest bidding vendor in MX or wherever. My take.

Seems I had rebuild kits for all 4 corners for barely under/over $100. Dan pricing so automatically ~2 yrs ago (more like 4-5 IIRC).

 

[Seth_O]

Search around Mud and you will see different opinions. Toyota doesn't have instructions to split the caliper apart nor is there a replacement seal available from Toyota. However, others say a standard brake shop will have this seal if you split the calipers. One thread had identified the seal dimensions.

This was fresh in my mind from my recent endeavor on caliper rebuilds.

John

Cheers john. I hunted around, but couldnt find anything. Ill keep looking.

 

[ewillis]

Check @jonheld threads...guy's a caliper rebuilding savant.

 

[Alic]

Split them and reuse two samll seals. I did it every year for 5 years to rebuild my calipers after swiming summer season

 

[bigCatdiesel]

Search "caliper rebuild question" and you'll see the conversation I was referring to.

John

 

[jebber]

I know what you mean about brakes, the 80 series and near misses. I just installed a set of Terrain Tamer HP rotors and brake pads. They definitely out perform OEM, I'm happy. Replaced the break booster and master cylinder a few months ago. I haven't touched the calipers yet.

 

[Seth_O]

Any thoughts on the advisability of hot tanking the calipers?

 

[Seth_O]

Well, I made some progress on the rebuild this weekend. I spent a little time trying to get the pistons out w/o any success. A quick search on Mud revealed the 'compressed air' method.

I picked up a full set of used lines from a mud member (more on that later) and took an original caliper line and bolted it up, and then cut off the other end. This let me stick an air hose onto it.

Skipping to the punch-line the compressed air trick totally worked, but when those pistons/cups come out, they come out with a POP! I learned after the first one to stick a block of wood in there to catch it. I also found that on the front calipers the 4 pistons come out at different times, so as each one was about to come out I would stop, loosely put a C-clamp on it so it didn't pop and the go back to the air. I did this until I had 3 pistons with clamps on, then the block of wood and blow the last one out. Then I could go back and remove the remaining 3 pistons by hand.

I went ahead and bought the dorman brand rebuild kits (at $9 ea it was worth it) so I could get the small flat washer. Since I have that washer I felt ok to peel the calipers apart. Although once I did I found the washers to be in remarkably good condition.

I also took a moment to look at my leftover '02 Sequoia front calipers. They are extremely similar, down to the same size and location of mounting holes. I think its possible they would be interchangeable with very little modifications (if any.) Looking at the '02 calipers I don't think there would be an advantage to it per se (other than in my case its 20yrs newer), but a common mod in the early sequoias is to replace the calipers with some from a later model sequoia (my '02 has '05 calipers) because they give better braking performance. The '02 to '05 swap is a bolt-in, just have to trim the dust shield a little. It makes me wonder if you could put '05 sequoia calipers in the LC and get upgraded performance?

I was pretty pleased with the condition of the calipers and pistons when I got them apart. The plan is to get the calipers hot-tanked and then painted and I'll reassemble with 100 series pads.

On to the pics.

Here's how the evening started:

LC caliper on the left, Sequoia on the right:

The mounting ears are identical

Unfortunately no pics of blowing the pistons out, but after removing them I cleaned them up on the buffer wheel on the bench grinder:

Im pretty pleased with how they look, no rust or pitting at all. They should seal up real nicely with all new rubber. Not sure how long til I get to the next step, but making progress.

 

[jonheld]

FWIW, I went through this on my LX450 last spring. I used all OEM parts.
4 new rotors, removed, cleaned and rebuilt all calipers, new soft brake lines, the whole shebang.
The OEM caliper kits don't supply enough grease IMO, so I used Amsoil moly on the pistons, rubber, and all moving parts.
I paid very little attention to the outside of the calipers other than cleaning them. They are simply a pressure vessel.

Once it's all back on the road, don't forget to activate the ABS several times to cycle the old fluid out of the ABS system. Then flush the fluid again.
Here's a neat trick:
Quick and easy brake line banjo plug

 

[MDarius]

Well, I made some progress on the rebuild this weekend. I spent a little time trying to get the pistons out w/o any success. A quick search on Mud revealed the 'compressed air' method.

I picked up a full set of used lines from a mud member (more on that later) and took an original caliper line and bolted it up, and then cut off the other end. This let me stick an air hose onto it.

Skipping to the punch-line the compressed air trick totally worked, but when those pistons/cups come out, they come out with a POP! I learned after the first one to stick a block of wood in there to catch it. I also found that on the front calipers the 4 pistons come out at different times, so as each one was about to come out I would stop, loosely put a C-clamp on it so it didn't pop and the go back to the air. I did this until I had 3 pistons with clamps on, then the block of wood and blow the last one out. Then I could go back and remove the remaining 3 pistons by hand.

I went ahead and bought the dorman brand rebuild kits (at $9 ea it was worth it) so I could get the small flat washer. Since I have that washer I felt ok to peel the calipers apart. Although once I did I found the washers to be in remarkably good condition.

I also took a moment to look at my leftover '02 Sequoia front calipers. They are extremely similar, down to the same size and location of mounting holes. I think its possible they would be interchangeable with very little modifications (if any.) Looking at the '02 calipers I don't think there would be an advantage to it per se (other than in my case its 20yrs newer), but a common mod in the early sequoias is to replace the calipers with some from a later model sequoia (my '02 has '05 calipers) because they give better braking performance. The '02 to '05 swap is a bolt-in, just have to trim the dust shield a little. It makes me wonder if you could put '05 sequoia calipers in the LC and get upgraded performance?

I was pretty pleased with the condition of the calipers and pistons when I got them apart. The plan is to get the calipers hot-tanked and then painted and I'll reassemble with 100 series pads.

On to the pics.

Here's how the evening started:View attachment 1409856

LC caliper on the left, Sequoia on the right:

View attachment 1409857

The mounting ears are identicalView attachment 1409858
Unfortunately no pics of blowing the pistons out, but after removing them I cleaned them up on the buffer wheel on the bench grinder:

View attachment 1409859

Im pretty pleased with how they look, no rust or pitting at all. They should seal up real nicely with all new rubber. Not sure how long til I get to the next step, but making progress.

In your second picture the calipers on the right look like cute little baby calipers compared to the set on the left. Is that an illusion due to camera angle, or am I right? Do they actually measure the same?

 

[Seth_O]

In your second picture the calipers on the right look like cute little baby calipers compared to the set on the left. Is that an illusion due to camera angle, or am I right? Do they actually measure the same?

Its the angle of the pic, they are exactly the same size. Heres another shot:

 

[Seth_O]

Got the calipers cleaned, painted and rebuilt using the OEM rebuild kits.

Not real hot on the color, but thats what I had enough of laying around.

 

[Seth_O]

Got the calipers mounted up, and (after some drama) all new soft lines. The axle lines got about 2" of extension in case I ever want to do a small lift.

.

 

[Seth_O]

Yanked out the ABS. I have plans for that space....

 

[Seth_O]

When I removed the LSPV I kept the 90* union and bracket from the drivers wheel well. I flattened it out with my bench vice and it fit perfectly in place of the LSPV.

 

[Seth_O]

I kept the T in place underneath the MC and routed my lines through there. This worked great, except it sprung a leak

 

[Seth_O]

I really liked how it mounted on the booster though, so I ponied up for an OEM replacement. That arrived this afternoon, so I finally got it installed and buttoned up. No more leaks!

I bled the brakes until nothing but clean fluid came out at all 4 corners. Threw the tires on and backed it out of the garage.

And barreled into the street because the brakes wont stop the truck

 

[Seth_O]

I have spongy pedal all through the travel. If i pump fast and hard it firms up a little, but a few seconds later goes back to soft.

Pretty frustrated at the moment.

Could the MC have coincidentally gone out right while I was working on the brakes?