Blown Brake Master Cylinder?

[The Dark Side of Will]

I'm getting the Storm Trooper (white Formula) back on the road after sitting while I was in Iraq. It needs clutch hydraulic work. As of last week it also needed rear brake calipers.

I ordered a pair of rear brake calipers for it last week. I tried to install the left one earlier today only to have the banjo bolt threads pull right out. I helicoiled it and it seemed to take.

I was maneuvering the car to turn it around for more convenient access to the right rear caliper. In mid turn, the pedal went to the floor. I was going about 0.5 mph and the RR caliper is dragging, so nothing interesting happened.

I had my dad push the pedal while I felt around the new caliper... no leaks. I had him pull the lid off the reservoir and watch while I cycled the pedal. He said there was a "fountain" of fluid in the rear compartment of the reservoir when I was pushing the pedal.

Sounds like an internal MC seal took a dump.
What says RFT?
Recommendations for or "stay aways" from any particular brand of reman units?

[The Dark Side of Will]

So the RIGHT rear caliper let go of its banjo bolt threads also. Sigh.

[Series8217]

Yeah, the fountain of fluid on the MC with the cap off is normal behavior. I don't recommend trying that again, someone is destined to get some brake fluid in their eye, and it usually makes a mess of the front compartment...

[CincinnatiFiero]

My Benzes I bleed with the MC cap off, just have my girlfriend top off as shes working the pedal. However on the 88 bleeding with the cap off once resulted in brake fluid as far away as the trunk with a good stab of the pedal. So that's normal.

[AkursedX]

I hate to say that both the M/C fountain and the leaking are both normal things. I have found that nearly every rebuilt '88 caliper I have ever bought have leaked from either the banjo or the bleeder. The aluminum seems very brittle and both the stock threads and even new helicoils have a hard time staying threaded. I have had much better luck with rebuilding old stock ones.

[The Dark Side of Will]

I was pushing the pedal very slowly to avoid spraying brake fluid everywhere.

So far the helicoils have held. I use a bending-beam torque wrench and with that I can watch the copper washer cold-flow as I tighten the banjo bolt. We'll see how long it stays. One of the calipers already had an insert in the bleeder hole. The two calipers also had mis-matched bleeder screws.

Having worked extensively with Northstar engines, I'm familiar with the problems GM's aluminum casting alloy has with holding high-load threads when it gets old.

No visible leaks... just no pedal. The "fountain" seems strange, but I've read a little bit about the "quick-take-up" mechanism in the '88 MC's; I'm @$$uming the fountain is a result of that.

Anyone think it's something *OTHER* than the MC?

[The Dark Side of Will]

YUM.

[AkursedX]

I hate that sight. But on the bright side, at least it's not from a northstar block!

[Emc209i]

Reminds me of an 18-135mm lens.

[The Dark Side of Will]

I was reasonably impressed that my 6 year old Kodak could get that close...

[fierogt28]

Guys, the squirt from the master cylinder is normal with the top off. That goes for all fieros.

BTW, on one of my 88GTs I bled the whole system 3 weeks ago. Make sure the banjo bolts is torqued to spec (33ft/lbs) from the 88 service manual. I didn't notice that banjo could back out. I'll check the torque on them next time I have the wheel off. (Don't worry, I will. Takes 2 minutes)
Also, you can re-use the copper washer on the banjo bolt, but that's your choice. Its always good to install new since your there. (have it apart)

I closed the MC cover everytime and checked so the brake fluid would say above 1/4 just to be safe. It was time to flush the system.

Now these days because the fieros are getting up in age, install all new bleeders. Its worth it if you can get all bleeders out with success. You certainly don't wanna have one break on you while doing a system bled. Cost 10$ for 4 bleeders than 100$ just to change to a rebuilt caliper. Put a dab of anti-seize on the bleeder just to safe. You don't need to tighten the hell outta the bleeder bolt. 8-9 ft/lbs is plenty.

[The Dark Side of Will]

Regardless of the status of the fountain, the pedal still goes to the floor without visible leaks.