I'm getting close to wrapping this project up so I thought I would post a couple of photos since things have been pretty quiet on this forum for a while. I tested it out the other day in the neighborhood and the caliper mounts that I concocted seem fine so far but I think I need a larger master cylinder since the pedal has too much travel and is a bit soft. I can still lock them up easily however so I may not be that far off. I will hopefully get a response back from Tilton tomorrow.
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the Motive power bleeder (www.motiveproducts.com) is one of the best tools in my shop have not had any bleeding issues since it's purchase. Calpers look good, will be interested bin where you end up on cylinder size.
Sweet! Unless they're way off and it's dangerous, I'd wait till you get them well bedded before you playing with sizing. Then, after they're nice and hot, dial in the bias till the fronts lock sliiiiighty before the rears...the sliding end will always lead the car.
A roadside camcorder can give you all the info you need for adjusting bias if it's not obvious from the cockpit.
Even if you can lock them, a long pedal can get you into trouble when the fluid gets hot...near boiling.
I assume you have braided lines and you pressure bled them, right? Ed
Yep have braided lines but had to replace the old braided lines with new longer ones (18").
I have bled the thing to death with a vacuume bleeder (pretty worthless) and the old tried and true pump til you drop and no more bubbles seem to be coming out. The pedal did firm up a good bit but is not improving at this point. I never had a problem bleeding them this way before so I guess there is always a first time. Anyway even at rest I can easily put the pedal to the floor but it does not slowly drop or pump up and become firmer. It engages and the pedal feels consistent but is much softer than before.
I did some quick calculations on the piston area size of the old C4 single piston and the new caliper pistons and there is a significant increase in area. The good thing about Tilton is that they will give me the proper size front and rear master cylinder sizes based on a lot of factors on the car including weight, weight distribution (fore/aft), wheelbase, wheel diameter, piston sizes, pedal ratio, and use. They may come back and tell me to use the same size I have now and then I know its a bleeding issue but I am betting due to the big increase in piston area the master needds to be larger.
I bought a hand-pump pressure bleeder, and love it.
Unless the lines are growing (have somebody push the pedal and grab each line...you'll feel it), it sounds like either air or silicone fluid. I don't use silicone. DOT4 Castrol for this old-school boy.
Don't forget to hit the calipers with a brass hammer while bleeding. I've seen bubbles dislodge after a good tap.
If pumping doesn't change resistance or move up the hard spot, it could be a sizing issue or a BIG air bubble.
I was looking to add a pressure bleeder to my tool collection but I can't find one in town so it will be an online purchase and several day shipping delay but I expect to oder one up tomorrow. Are you using the Motive unit or something more elaborate? I thought about making one out of a generic sprayer from Home Depot (seen other folks to this) but really did not have the time. Bad thing was that this caused me to miss going to the track this weekend. I guess I will just have to make up for it and go more days next month... ;-)
The lines are not growing, I was checking them for vibration/bubbles while my wife pressed the pedal during our bleed fest. They are pretty good quality lines from a local race car supplier who outfits a lot of the local serious racers. I did the whack it with a hammer thing on the calipers and the master cylinders as well but used a rubber mallet. I have not tried bleeding again after the road test but was hoping that if there are bubbles then maybe some heat would move them a bit more.
Replies
the Motive power bleeder (www.motiveproducts.com) is one of the best tools in my shop have not had any bleeding issues since it's purchase. Calpers look good, will be interested bin where you end up on cylinder size.
Jack
A roadside camcorder can give you all the info you need for adjusting bias if it's not obvious from the cockpit.
Even if you can lock them, a long pedal can get you into trouble when the fluid gets hot...near boiling.
I assume you have braided lines and you pressure bled them, right? Ed
I have bled the thing to death with a vacuume bleeder (pretty worthless) and the old tried and true pump til you drop and no more bubbles seem to be coming out. The pedal did firm up a good bit but is not improving at this point. I never had a problem bleeding them this way before so I guess there is always a first time. Anyway even at rest I can easily put the pedal to the floor but it does not slowly drop or pump up and become firmer. It engages and the pedal feels consistent but is much softer than before.
I did some quick calculations on the piston area size of the old C4 single piston and the new caliper pistons and there is a significant increase in area. The good thing about Tilton is that they will give me the proper size front and rear master cylinder sizes based on a lot of factors on the car including weight, weight distribution (fore/aft), wheelbase, wheel diameter, piston sizes, pedal ratio, and use. They may come back and tell me to use the same size I have now and then I know its a bleeding issue but I am betting due to the big increase in piston area the master needds to be larger.
Unless the lines are growing (have somebody push the pedal and grab each line...you'll feel it), it sounds like either air or silicone fluid. I don't use silicone. DOT4 Castrol for this old-school boy.
Don't forget to hit the calipers with a brass hammer while bleeding. I've seen bubbles dislodge after a good tap.
If pumping doesn't change resistance or move up the hard spot, it could be a sizing issue or a BIG air bubble.
Keep me posted on this.
The lines are not growing, I was checking them for vibration/bubbles while my wife pressed the pedal during our bleed fest. They are pretty good quality lines from a local race car supplier who outfits a lot of the local serious racers. I did the whack it with a hammer thing on the calipers and the master cylinders as well but used a rubber mallet. I have not tried bleeding again after the road test but was hoping that if there are bubbles then maybe some heat would move them a bit more.
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