TT331FB hits the road!

R100RT

Founding Member
Nov 27, 2000
362
0
16
Sonora, CA
I had a big day today! I got up the nerve to take TT331FB for a spin. Given that my fuel pressure, boost pressure and RPM inputs are not online yet, I wanted to just go for a short lap around the house. First, the bad..

My trac-loc is making a lot of noise when I turn. The noise is worse when costing and much better under acceleration. As soon as the front wheels are straight, the noise goes away. I rebuilt this myself so I don’t know if I messed up or if it is normal to make noise for a while. Perhaps, some one knows this and I would like some input. Second, I cannot get my brake pedal up. I have tried everything. I re-bleed the MC, power bled the rest, bled each fitting, bled the proportioning valve and the pedal still goes almost to the floor. I checked the rear caliper adjustment and tightened it up a little. I’m to the point that I suspect MC problems and I plan to try another one. Observing the operation, with the cap off, I see that the piston is moving as soon as I start to push the pedal. The rear reservoir has a good stream of fluid the pushes out of the air vent. The front doesn’t do this at all.

The good news…I have created a monster! Under just vacuum, the engine pulls well and you can spin the tires just with moderate gas pedal. I made a few short pulls under boost. In second gear, I applied about half throttle. The boost came up to about 6 PSI before I let off the gas. As the boost came on, the rear tires came loose! I can’t even comprehend what 12 PSI is going to feel like! This car pulls hard and I haven’t even got the throttle opened up yet! I have chased down all the leaks. I have lots of aluminum and things that were tight get loose when hot. The fan is doing a great job of keeping the engine at 180-185 DEGF. I haven’t seen the oil cooler come on yet.

When I get the brakes checked out, and all the data logging up and running, I will try more pulls. Until I can relate A/F to boost and RPM, I am hesitant to push the motor.
 
this may not be it, but I had the same problem with my disc brakes on my '68. I rebuilt the entire system and still could not get a pedal. Turned out that the previous owner had installed the calipers on the wrong wheels, so that the bleeder screws were too low to let air out when bled. Bleeder screws should be at the top of the caliper, but I never thought to check this FIRST. Needless to say with an air pocket trapped there was no way to establish a pedal. I took the calipers off and installed them to the correct left and right wheels, and my brake pedal is fine. Hope this helps.
 
The other thing you can check is the cigar shaped 'metering valve' which is mounted in-line for the REAR brakes. This helps establish a firm brake pedal. The valve should be against the fender apron under the master cylinder and next to the prop valve. If you need that part, www.mpbrakes.com has them for under $30.00. You would need a 10psi rated valve.