Brake Caliper Rebuild Problems...

[Flinkly]

i was going to rebuild the calipers that came on my mk3 gt6 myself, but not only is one of the pistons stuck in the caliper, but that same piece is a 16pb while the other caliper is a 16p. i remember reading recently that these do not take the same piston, and am now wondering what it is that i have. the designation is only on one side of the caliper, so i'm not sure if i've got one complete 16p and one complete 16pb, or 3 halfs of one and 1 half of another...soo confused.

this was supposed to be easy. didn't want to have to, but i might order two rebuilt 16pb's and send these mismatched ones in as cores. another 100 dollars overbudget.

i guess i could find some used ebay calipers and rebuild those...

 

[DNK]

The PB used imperial threads and used a different piston than the MP version which used metric threads

 

[trrdster2000]

Flinkly, Get someone to mic the pistons and see if they are the same. If they are no problem. I would think it would be hard to find pistons in good shape after all this time, but I have 2 in the basement off a '70 GT6 that I will tear down and check them if you can't find something your way.
My son is in Seattle and says there are lots of TR's around, but some things are hard to find.

Wayne

 

[PeterC]

First, the piston bores are the same, so no worries on brakig effectiveness.
The difference is in how the outer dust seal is retained.
The 16P caliper dust seal is made so that the outer lip is formed to fit into a very thin groove in the bore and the inner lip of the dust boot fits into a thin groove in the piston. The piston holds the outer lip into the bore.

The 16PB caliper has a raised edge or boss around the bore diameter that accepts the outer lip of the dust boot and which is retained by a metal clip or split ring. The piston for this caliper has a groove around 1/8th inch to accept a thicker lip on the inner portion of the boot.

I hope that helps.

Peter C.

 

[RonMacPherson]

You should be able to get repair kits, and pistons, and the o-ring that goes between the caliper halves from BP Northwest at a very good price.

 

[brent615]

just did this myself on my tr6. used TRF rebuild kit and TRF stainless steel pistons. tried for two hours to get my pistons out. gave up, took calipers to Midas. they used a blast of compressed air to pop out the stuck piston. i used a medium size C clamp and an old brake pad to push the new pistons in slowly and evenly.

i suggest replacing your flexible brake lines at the same time. i found one of mine was 60-70% blocked.

i also replaced the bleeder nipple with Speed Bleeders. very cool gadget. made bleeding easier and cost about $20 for 4.

 

[70herald]

I also just my brakes back together. I popped the pistons out with the master cylinder. After I replaced the rings on one side, I held the completed side in place and pumped the second piston out. Lubricate the o-ring with brake fluid and the piston should press in fairly easily.

I did have a major problem with the first set of o-rings which I got. They were rather old ( a bit dried out) and not quite as soft as they should be. They didn't work well. The second set I got were fresh just a bit softer. The piston went in very easily.

 

[jdubois]

tried for two hours to get my pistons out. gave up, took calipers to Midas. they used a blast of compressed air to pop out the stuck piston.

I just had to get stuck pistons out of my Spit's calipers. Only one of the four would come out using the master cylinder. Since I was replacing the seals and pistons anyway, I soaked the pistons liberally with WD-40 and waited for about a half-hour then pounded the pistons back into the caliper all the way by sticking a small scrap of wood inside the piston and hitting it with a hammer. That one two combo loosened them up enough that I could get them out by levering with two screwdrivers on opposite sides, in the dust seal groove. Agressive approach, I know, but it didn't seem to cause any damage to the calipers.

 

[sail]

To get my pistons out which sat for 15+ years I attached the hose from a foot bicycle bump to the inlet, put a piece of wood in between the pistons and blew out the first one partially. Then using a piece of wood clamped the loose one so it wouldn't come out any further but allow the second room to get loose. Worked great, I just can't pump up my bike tires anymore as the fitting had to be cut off the hose to attach with a hose clamp to the caliper inlet.

 

[Flinkly]

so, should i try to find two 16pb imperial calipers (what i should have) or buy the 16p calipers that are now on ebay and call it good? i'd like to keep this the way it should be since it shouldn't be too hard to find two. no need to mess up originality if i don't need to.

i'm looking for used ones and i'll rebuild them myself, in case anyone has a set of 16pb imperial calipers just sitting around. i'll even send my mismatched set back for the core charge!

 

[MadRiver]

If you use the compressed air method (which I did), make sure to put a large rag over the capiler. There may be some old brake fluid in there, esp. if you recently took them off the car. Unless you had already switched to DOT5, you don't want that fluid spraying everywhere. Actually, DOT5 is kind of hard to mop up, so even if you switched, you don't want it spraying everywhere!!!

 

[TR3driver]

Actually, DOT5 is kind of hard to mop up, so even if you switched, you don't want it spraying everywhere!!!

/bcforum/images/%%GRAEMLIN_URL%%/iagree.gif Particularly if you ever plan to paint in the vicinity !

 

[Jon80spit]

I tried the compressed air trick with no joy. I found that an old rubber brake hose fit in my grease gun. Worked great! Then used thinner to clean out all the grease.