1st gen VR4 brake conversion big issues :(

[TUFFTR]

Okay, so should I take the front brake lines off and blow em out or something? how should I go about this? I am having a DIY day on the weekend with some mates (took an engine and gearbox out at my joint so it's all going back in this w/e) so if I had some steps to cross off so to say I could knock down a few possibility's this w/e.

So yeah, Must be in the calipers or lines as the previous lines and calipers worked fine! I just got greedy and wanted bigger

[GTOJOE]

Just re-bleed the whole thing. If they bleed fine then there is nothing stuck in them. Report back after this. Also the lines you are talking about... did they come with the GTO calipers? Have you check them? maybe they are swelling which is reducing your braking efficiency? None of this howevr explains why you would be getting fluid overflow.

[TUFFTR]

Yup. That's the problem. The fronts bled fine. hell just this week I did 2 brake bleeds. and like you can tell when there is an issue with pressure compared to the process going by the book.
So fucking weird. I just dont wanna bleed the whole system for no reason. Guess I might just to say It's done. Who knows. Pressure buildup is making me confused. Anyone else got some pointers? Sigh. Nothing ever goes right for poor pauly.

[tabasco122]

if you disconnect the front, you need to bleed the rear. there is a reason you bleed the brakes in reverse order. if you take off the brake closest to the MC (front driver usually) then you have the possibility of letting air into the whole system. just bleed them all, starting from the rear pass>rear driver> front pass > front driver

[TUFFTR]

Spoke to a brake guy today while getting some disc's for my mate's car with my situation and he said, like I suspected, if it's only happened once the calipers have gone on. It's probably the calipers. ordering a rebuild kit on monday from rockauto.com and in a few weeks will take them apart and see what the hell is going on.

Should I actually SPLIT the calipers apart or just do the pistons and seals and lube em up?

[TUFFTR]

should I get the master cylinder anyway off a VR4?

[GTOJOE]

Just try the caliper rebuild first. I don't think you will need to split them. Just change all 4 seals and boots and clean them and try again. Split them if you want to though. Who's car did they come off?

[TUFFTR]

Ahh well, my mistake really. they were sitting for a good 3 years off a car. Got it off a member of AMC who just had em laying there and needed the $.

Mmmm.....I'll do that. Even though I can see they are somewhat clamping I will do one thing at a time. I'll blow out the brake lines aswell just incase.

[TUFFTR]

Think I may of found a cause *hopefully not tested yet* which seems very logical and possible.

Disassembled both calipers, cleaned up the dust boots, recoiled the bores, checked for rust etc, what i noticed was a lack of lubrication on all 8 pistons/bores and the fact even with a full air compressor it was almost impossible to push the pistons out (due to lack of lubrication?) so I've reoiled everything and cleaned it all up, seems alottttt smoother now. Tomorrow or tues will rebleed and see how we go!

[GTOJOE]

Don;t think they need any oil/lubrication. The brake fluid is all the lubrication needed. Perhaps the issues are from the pistons not moving well but all you need to do is clean then [wet sand with very fine paper if they need it] and reassemble. Don;t use oil. When inserting the pistons back in wipe some brake fluid on them to help slide them in.