Chasing a firm brake pedal, What next? Options

[robkammer]

Teeners: It's been over two years since our 74 BB arrived. A Caliper blew out as it came off the transporter in 12 degree temps. Really no surprise as the PPI pointed out a leaky caliper. So I did what I thought would be appropriate for this little beauty, I sent all of the hard bits out, calipers and regulator, to a widely recognized firm for 'restoration'. Put in a new EZ master from 914. And all should have been fine. But, even now, after 1800 miles, a second set of calipers from the 'restorer', a new ATE MC from the restorer. ( I threw out the EZ MC). I still have squishy pedal.
I do not suspect the pedal box area as the car has absolutely no rust.
I just rebuilt the 'restored' front calipers with new square cuts from AA, took out the springy metal pieces that are supposed to keep the pistons from rotating, and the pedal is much better. I have about 50 miles on this but after bleeding it again the bleeders were leaking and I put it back on the lift. ( I was told: maybe: we left the calipers in the acid too long)
So: Now that the pedal seems like I might be on my way to GOOD braking, I can hear the pressure regulator knocking when I press the pedal, at a standstill, in the shop. Is this normal and to be expected? Note: During attempts to bed the brakes and get them working, I was only ever to lock up the rears, and it was really difficult to do. ( difficult may not be accurate, violent might be more appropriate)
The newly rebuilt calipers seem fine, just like the calipers in my 911's that I rebuilt.
As for bleeding, I've done it every way known to man. And some new ones too. Just picked up a 6th quart of Super 4. $26.00!!! A fifth of Weller was only $23!.
I'm really frustrated with this little car. Any input will be appreciated.

I'm thinking of putting in a Tee in place of the regulator, just for testing. If anyone has a Tee that they would be willing to let me borrow, I would be willing pick up all of the shipping just so I don't have to mess with the fab work.
Thanks,

[iankarr]

You've gotten great advice in this thread. Also important to keep in mind that it's normal with these cars/calipers for it to be a bit of work to get firm pedal when the system is fresh. There are literally dozens, if not hundreds of threads about trying to get a hard pedal. Just to summarize, in order (with a few things that have worked for me)...

– "Bench Bleed" master cylinder first (see video in my signature for how)
– Replace rubber lines
– Ensure venting clearance is correct
– Replace bleeders with speed bleeders
– Use a motive pressure system AND stomp on the pedal (this is where the speed bleeders really help)
– Repeat bleeding 2-3X
– If pedal is too soft to drive, crack the fittings on the regulator and pump pedal (closing after each pump) to get air bubbles out. Can also tap with a hammer.
– If pedal is STILL too soft, try using a syringe to shoot fluid through the bottom bleeder, with the upper one open
– Take the car for a bumpy drive
– Bleed again
– Bed the pads
– Pedal will not be rock hard for about 100 miles or so...until the seals loosen up.

As Superhawk mentioned, you definitely want to keep that regulator in service. Otherwise you run the risk of the rears locking up before the fronts, which could be a really dangerous thing.

One general note...I'm an amateur mechanic who knows just enough to get by...and sometimes get myself into trouble. If I send something out to be restored by experts...especially experts who specialize in something...and I can't get it to work, I generally assume the problem is mine – not the shop's. Of course, things can and do happen. But if you're still learning, like I am, jumping to conclusions that a shop didn't do right by you may not be fair. Just my .02

Hang in there!