CSRP Disc Brake Swap Problem

sparx · Mar 11, 2011

I finally got to bleeding my brake system today, I have the CSRP disc brake upgrade kit, front disc rear drums. Before I installed the master, I bench bled it. All lines are new and there are no leaks.

Well, today I got all the air out of the lines but I got no firmness in the pedal.

I redid the master bench bleed on the car this time, still no pedal firmness.

First thing I can think of is the master is bad, or I did not bench bleed it properly.

Also does anyone know what year this dual res master is from?
Sparx

DukeGnarley · Mar 12, 2011

Are you using a brake booster? If so, are you sure the push rod is making contact with the master cylinder?

2+2GT · Mar 12, 2011

DukeGnarley said:
Are you using a brake booster? If so, are you sure the push rod is making contact with the master cylinder?

Excellent question. A shop near here ran into that problem with a CSRP booster recently.

sparx · Mar 12, 2011

No booster -- manual brake system.

I think I will pull the master and bleed it on my bench and try again.
At least I have no leaks that is a good thing.

Bleeding brakes bleeds the mechanic too!
TY
Sparx

degins · Mar 12, 2011

2+2GT said:
Excellent question. A shop near here ran into that problem with a CSRP booster recently.

I believe that the OP has resolved this issue as a failure to bleed the system.

2+2GT, the problem that your employer (Glazer-Nolan) had with the booster was entirely an installer issue. I spent a lot of time with tech service on this issue and extended the courtesy of sending a replacement booster, even though I was sure the the first booster was OK.

sparx · Mar 12, 2011

Good news, I removed the master cylinder and bench bled it again so I do have brakes.

I do need to determine how to adjust the proportioning valve and have question on free travel of the brake pedal. I have a firm pedal, but there is about 2" of free travel before any braking occurs.

Is this corrected by adjusting the rod length?

Also Dennis of CSRP was very helpful as always.
sparx

DukeGnarley · Mar 13, 2011

Usually the free travel is due to there being a gap between the rod and the MC. adjust the rod out to reduce the gap, but not so far that it's pushing on the MC when the pedal is all the way up.

2+2GT · Mar 13, 2011

degins said:
2+2GT, the problem that your employer (Glazier-Nolan) had with the booster was entirely an installer issue. I spent a lot of time with tech service on this issue and extended the courtesy of sending a replacement booster, even though I was sure the the first booster was OK.

I'm not currently employed by Glazier/Nolan.

I did see the boosters in question, and I was mystified by the way the pedal could travel to the the floor. Even a complete booster failure should not do that. I wonder how the internal parts could compress in that manner. Made me wonder if a stalled engine would make the brakes inoperative.

The installer was Fred Glazier, one of the founding MCA Gold Card judges, who knows more about these cars than you and I could ever hope to know, and has been working on stock and modified Mustangs as his profession for nearly four decades. I think we can probably eliminate "installer error". The car in question was running with no booster last I saw it, using the same master cylinder that was inoperable on the booster. Working perfectly, as was the rest of your excellent disc brake conversion, which they have always found quite satisfactory. They considered providing your airfare to come and show them how to make the booster work. Was that not a possibility?

Sorry to bring all this up on an open forum, but you opened that door, I felt compelled to respond publicly, although I'd have preferred a p.m.

10secgoal · Mar 14, 2011

sparx said:
I do need to determine how to adjust the proportioning valve and have question on free travel of the brake pedal. I have a firm pedal, but there is about 2" of free travel before any braking occurs.

This is normal with a small bore MC found in manual brakes. It take more travel to give the disc's the volume they need to create pressure. you find the bigger bore MC in power systems. They will travel less, but be MUCH harder to get the car to stop. That's why they are on power systems. You can buy an adjustable rod and put just a touch of pre-load, and that will help.

2+2GT said:
Sorry to bring all this up on an open forum, but you opened that door, I felt compelled to respond publicly, although I'd have preferred a p.m.

Actually, you opened the door with this.

2+2GT said:
Excellent question. A shop near here ran into that problem with a CSRP booster recently.

As far as what your guy knows, nobody is infallible. Don't care how long he has been doing it. My guess on the booster problem is that rod receiver in the back of the MC was too big for the rod coming out of the booster. The booster rod is VERY small in comparison. Which is probably why it works fine without the booster. The pedal rod is much larger and will always engage the back of a MC. I have always seen an adapter that goes between the two of them to make sure the boost rod actually pushes on the MC bore. The booster is mechanical. The power part is not. If the booster does not work, you will still have pedal, and the car will still stop. If the car does not stop, it obviously isn't operating the MC. This is very easy to figure out.This adapter is VERY common in aftermarket boosters, and I have seen it missing on other boosters not from him. Figured your expert could have figured that out pretty easily

CSRP Disc Brake Swap Problem

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