I am in the ending stages of a total performance 23t assembly and am having a great time. Few frustrations but the biggest now is a soft brake pedal. Have bled the system five or six times including a suction bleed at the four corners. No air in the lines but pedal is still soft. Brake tech who took a look at my sytem thinks the brake lines are installed backwards. I swear they are as Total instructed - front disc line to the half round reservoir nearest the rear end and the rear drum line coming from the larger, rectangular reservoir nearest the engine. Brian from Total if you are out there, can you help? Are they backwards? the pre-bent brake lines from Total lined up perfectly as described above. What am I missing? Brake Tech thinks pressure from the reservoir is there, but weak. Same at the four corners. Could the master cylinder be bad?
Hello from the new guy in San Diego
- Thread starter ptfinn
- Start date
EX JUNK
Moderator
Did you bench bleed the master cylinder? Many start up brake problems can be traced to this missed step.
Here are some links that you can check out.
Bench Bleeding of a master cylinder saves a lot of time and problems
How To Bench Bleed A Master Cylinder
Even a video:
How to Bench Bleed a Master Cylinder: Pt. 2: How to Install High Performance Brakes on a Custom Car | eHow.com
Jim
Here are some links that you can check out.
Bench Bleeding of a master cylinder saves a lot of time and problems
How To Bench Bleed A Master Cylinder
Even a video:
How to Bench Bleed a Master Cylinder: Pt. 2: How to Install High Performance Brakes on a Custom Car | eHow.com
Jim
Some single piston front disks, such as Wilwood, don't require a pressure retention valve. Actually, they won't work correctly with one. When I converted from dual piston calipers to single I simply ran a drill bid down the center of the valve to clean it out and then put it back in the line. I believe I read somewhere here that for the single piston setups the lines should be changed so that the large reservoir in the master cylinder feeds the front disks. Someone correct me if that is wrong.
Jeff
Jeff
Duke and 409T
Thanks for the response. I'm reluctant to change the pre-bent brake lines for this kit car as they fit perfectly when assembled so that the front discs come out of the smaller, half-round reservoir and the rear drums come out of the larger rectangular reservoir. Brake shoes are adjusted properly. I keep comng back to the check valve in the disc brake line and I think I'll remove that and see what happens. Does anyone think I'll replace one problem with a new one?
ptfinn
Thanks for the response. I'm reluctant to change the pre-bent brake lines for this kit car as they fit perfectly when assembled so that the front discs come out of the smaller, half-round reservoir and the rear drums come out of the larger rectangular reservoir. Brake shoes are adjusted properly. I keep comng back to the check valve in the disc brake line and I think I'll remove that and see what happens. Does anyone think I'll replace one problem with a new one?
ptfinn
LumenAl
Member
ptfinn said:
From one of my earlier posts...
When using a dual master cylinder with Disc front, Drum rear combinations you need residual check valve for the rear or better yet use a adjustable proportioning valve. Typically the large reservoir side is for the disc brakes, and the small reservoir side is for the drum brakes. However, the best brake expert I know... Sir Patrick of Immense Girth... aka Fat Pat says and I quote:
Note: The only time I've heard Pat say to use the larger reservoir on the front disk brakes on a T-Bucket is if you are using the WILWOOD 175 single piston caliper with motorcycle style disk on wire wheels (like I have)...
Do not use a residual pressure valve with 4 wheel Disc brake systems. The residual pressure will cause the calipers to drag.
An adjustable Proportioning valve allows you to balance the pressure between the front and rear brakes for smooth safe stops, as disc brakes require considerably more pressure to operate than drum brakes. Without a properly adjusted proportioning valve, the drum brakes will lock up before the discs do which can result in handling problems. Proportioning valves are also useful on 4-wheel disc or 4-wheel drum brake systems, giving you the ability to compensate for tire size differences, weight distribution, etc.
Make sure that the bleeder valves on the calipers and the power booster point up when installed. Air cannot be fully bled from the system unless the valves are installed in the up position.
Note: This Diagram shows large cylinder going to front brakes which is more common, so on your T-bucket, it would be reversed.
LumenAl
Thanks for the great descri[tion and diagram. Mine is a Total kit with Wilwoof 175 series front discs. Total says to remove the check valve in the output port to the front disc line. That will be my first try to see if I can get a hard pedal. If ot, then I'll switch the brake lines to front large reservoir and back small reservoir but I'm a little reluctant to do that based on what FatPat says about the larger reservoir going to the brakes with the most rolling resistance. Maybe before I try that I'll take everything apart adn go back to square one, re-bench bleed the master, etc.
Thanks again for your good help.
ptfinn
Thanks for the great descri[tion and diagram. Mine is a Total kit with Wilwoof 175 series front discs. Total says to remove the check valve in the output port to the front disc line. That will be my first try to see if I can get a hard pedal. If ot, then I'll switch the brake lines to front large reservoir and back small reservoir but I'm a little reluctant to do that based on what FatPat says about the larger reservoir going to the brakes with the most rolling resistance. Maybe before I try that I'll take everything apart adn go back to square one, re-bench bleed the master, etc.
Thanks again for your good help.
ptfinn
:toast: Hi new guy, I'm from San Diego also, have an almost completed Total kit. I had the same problem w my brakes. after much trial & many errors I found two things. DON'T reverse the lines at the master cyl. Ok first when I bench bled the master I somehow got the plunger pushed in too far. So was only working on one side of the master. I had to use a air blow gun to pop it back into place and that improved my brake pedal 80%. Then I found a leak at one of the rear wheel cyl's. It was not the cyl but the flared fitting the wasn't exactly round. This was on a stainless line also. I re flared it, ( by heating it first) and my brakes are now great, Nice hard pedal. So get some one to pump the pedal for you & look especially close at each connection. I think you might find the problem. If I can give you some help, contact me. I'm in Ramona email me skip7547@cox.net. Good Luck & welcome to the club:welxome:
Skipperb
Thanks for the reply. Did you take out the check valve in the output port going to the front disc brakes ( I assume you have front discs)? How did you take it out? Did you put the funnel shaped piece back in afterwards? How did you do that? Did you leave the funnel shaped piece in the output port on the rear drum line or did you take that out too?
thanks again.
ptfinn
Thanks for the reply. Did you take out the check valve in the output port going to the front disc brakes ( I assume you have front discs)? How did you take it out? Did you put the funnel shaped piece back in afterwards? How did you do that? Did you leave the funnel shaped piece in the output port on the rear drum line or did you take that out too?
thanks again.
ptfinn
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