Getting ready to install the IRS I restored 16 years ago (don’t judge me:-)
The rear brake cylinders had port corrosion that I chose to ignore when I had them re-sleeved, but must now be addressed. The IRS is complete so I want to dismantle the minimum number of assembled parts to remove the cylinders for remediation and bench test. It would be nice to pull the entire caliper but I will settle for just the cylinders. Bentley and Haynes are a bit vague. Can anyone advise please? Note: these are front cylinders transplanted to the rear.
Are you saying you installed calipers that are normally used on the front wheels onto the rear wheels? Or normal rear brakes i stalled facing backwards From normal?
These are the ones normally used on the front wheels. I mention this because I believe they are larger, whether that is the body or just the bore, I m not sure.
The bore is considerably larger, being 2 1/8” instead of 1 3/4”. That will seriously change the braking dynamics of the car And not for the better. Back to your original question, I would expect you need to remove the entire caliper to get access to where you want to
Rick the two outside piston assemblies can be easily removed without any other disassembly. I’m told that the inner ones can also be removed but with more difficulty - and small fingers. A friend of mine did it, with the cage etc still in the car - I wasn’t around to hear him!
I’ll have to re-research the front cylinders on the rear subject, since this will be my opportunity to change my mind if need be. At the time, this seemed the way to go to improve braking performance if you also change the fronts to something like Willwoods. That was the plan back then.
How much you can do with the calipers in-situ depends entirely on YOUR particular hardware. Jerry Mouton used to be able to remove all four cylinders from his without removing the IRS from the car. On mine, I HAD to remove the IRS, the half-shafts and the brake rotors. The cutouts were simple too close to the cylinders to be able to get ANY tool on them. Even if I’d been able to get the bolts loose, there was not enough clearance to get them completely out. So, you need to look at what YOU have to work with, and decide what is possible. Just because someone else was able to do it in-situ is no guarantee you will be able to.
If the seat for the flare is corroded you have a serious problem. I had to junk resleeved calipers because the flare wouldn’t seat or seal. Now the first time I had steel lines (new). I have since replaced all lines with cuNi. Maybe, maybe they would have sealed with the softer flares. As far as I know you’d need to make a facing bit to clean up the seat and not foul up the threads AND remove the chips and swag after you cleaned them up. As I said, my many hundreds of $'s calipers are sitting in boxes because it isn’t worth screwing around with the seats, mostly because the pistons come out with such difficulty due to that useless pin inside the housing. I just got the brand new Japanese Nissan Dunlop pattern calipers and all is good (the “fronts” in the rear, as you did). BTW, with 4 piston Goodwood English calipers on the front the brake balance seems perfect - several really hard stops and no rear lock up and super straight stops. In my opinion these cars tolerate many reasonable mixture of piston size. Proven by use, as long as the fronts are bigger than the rears - not rocket science matching bore area and theory. You can go nuts allowing for disc diameter, clinch style, pad material, weight transfer and endless worry. Just check out some historic racers - they often have some mismatch (Mustangs, whatever). They work fine on the track if the ratios are reasonable.
Also - done the removal both ways, in car and on bench. Due to the pinion offset one bolt is hard to get at. Even with the unit out it is difficult. One half (left outer?) is doable in the car, the inner with the pinion offset of the diff case, I don’t think it would be worth it trying, even if you managed it.
So, sounds like it might be possible without major IRS dis-assembly, but maybe not. I’ll start with the most challenging bolt first and then decide. And then get emotionally prepared to maybe scrap my re-sleeved cylinders (sorry Dan/CJ:-)
The guy who gave us the car in the first place is literally one of the best tool makers in the country (2nd place in a nationwide tool making contest) with a CNC mill - my brother in law. Two set ups per caliper (must hold 90 degrees), thats 8 set ups for each axle. Then try to get the chips out without taking the pistons out. Taking a piston out of these things is no easy task if you don’t want to wreck stuff. Then… you roll the dice on the crap job the sleeve guy did on everything he touched. His brake masters wouldn’t return on spring pressure, etc. I was unable to use anything he did. He also LOST a master that I had a confirmed arrival at his shop, which he wouldn’t make good (sent him another one - mistake). Not worth the chance. All the new stuff I got worked perfect, it just isn’t worth using stuff that you have no confidence in. Getting a cutter with the correct angle, cleaning the swag, WAY too many variables when the base stock is suspect. Chucking the units up at 90 degrees is no problem for him, but a rookie with a drill press doing 8 of them, I don’t think so.
It wasn’t a guy anyone would use - I went by price, which was stupid.
There’s another angle to this tale also. I know why groups like ours don’t like or allow vendor bashing. The reason I went with this very incompetent place was that a known, and no doubt reputable place, was bad mouthed on the internet. It may have been just a one time deal or who knows what, but I should have looked at the big picture and went with the known quantity. Bashing people based on limited experience is not a good idea.
Here is what I used to fit in between the pumpkin and caliper to remove the 4 bolts attaching the piston. It is a 1/4" drive Craftsman with pivot head and a 3/8 socket that I ground down a little. I was able to remove all 4 pistons without dropping the IRS. Best I can tell from your photo I think I have the same caliper.
That one bolt is so incredibly tight perhaps because I used front cylinders which maybe have larger bodies. No room for a 1/4" drive breaker bar. Ended up cutting a socket nearly in half and then making a handle with a tiny 1/8" high 1/4" drive nub. Just barely got it out. You can just make out the socket and wrench in the gap.
So, with the cylinder out, inspection reveals the port is trash. Not even worth trying to repair. At the risk of thread drift, can anyone recommend replacements? And I guess related to the same question, what is the latest thinking on front brake/rear brake choices today? I need front brakes too.
