Brakes pedal feels soft

[lfalzarano]

After driving my wife Cadillac for awhile, I took my Z out for a run. The pedal feel felt soft compared to the Caddy and it seemed to take farther to stop then I remember.

I checked the brake fluid reservoir, and the front on was slightly low, but well above the min line. The rear one was full to the top.

Any suggestions to proceed in identifying the lower perceived braking performance. Pads were replaced at 50K miles and the car has 85K now. The brake master cylinder was rebuilt 6-7 years ago. The car is driven 15 miles twice a month for the last 6 years.


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[ImpalaDave]

I'd recommend flushing/bleeding the brakes. I had a soft pedal and dragging brake issues when I bought my 40k mile Z, bleeding them fixed it. There was some black stuff that came out, I think it was rubber dust suspended in the fluid.


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[LGAFF]

I think its the nature of the brakes to some extent, is the other car electronic braking? I have read switching to a camaro master cylinder helps with pedal feel

[32valvesftw]

I'd recommend flushing/bleeding the brakes. I had a soft pedal and dragging brake issues when I bought my 40k mile Z, bleeding them fixed it. There was some black stuff that came out, I think it was rubber dust suspended in the fluid.


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The first thing I would do is replace the brake fluid. I like DOT 5.1 and run it all my cars. If you dont have stainless lines your lines may be aging and getting squishy.

[DRM500RUBYZR-1]

The first thing I would do is replace the brake fluid. I like DOT 5.1 and run it all my cars. If you dont have stainless lines your lines may be aging and getting squishy.

:thumbsup:

replace rubber hoses;
flush;
fill.

Easy and inexpensive.

Evaluate and update us.
:cheers:
Marty

[lfalzarano]

:thumbsup:



replace rubber hoses;

flush;

fill.



Easy and inexpensive.



Evaluate and update us.

:cheers:

Marty



Marty, do they make stainless steel ones for our cars or should I stick to the original rubber ones?


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[Paul Workman]

:thumbsup:

replace rubber hoses;
flush;
fill.

Easy and inexpensive.

Evaluate and update us.
:cheers:
Marty

:thumbsup:

DOT 3 fluid absorbs water which in itself will cause the fluid to turn dark, along with deteriorating rubber seals too will result in darkening. And, of course AIR in the system results in spongy brake pedal and (in severe cases) cause the calipers to drag. So, I agree w/ Marty 100%: REPLACE the hoses, FLUSH, and FILL. (I'm using DOT-3 fluid and check it and replace it annually. No problems with peddle firmness or braking w/ my J55 (stock) calipers.)

[DRM500RUBYZR-1]

https://www.ebay.com/itm/373118465587

corvette central

stainless are near forever; rubber will need to be done again.

same labor, so go with stainless!

:cheers:
Marty

[lfalzarano]

Thanks Marty for the link. Just bought the last one.


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[-=Jeff=-]

If the rear is full to the top (above max) and the front is low, you need a new master

[lfalzarano]

If the rear is full to the top (above max) and the front is low, you need a new master



jeff, you?re breaking my heart out now. I replaced the Master 7 or 8 years ago. What makes you come to that conclusion or is it experience? I appreciate your input and yes that it could be a probable cause. Thanks


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[-=Jeff=-]

Experience.. question to help me diagnose

Go out to car, start it, depress brake, release depress again right away.

When depressing the brake note travel each time.. are they the same or different travel distances

[lfalzarano]

Tested several times and the travel distance was the same.

In the comparison, I do know the wife?s Cadillac downshifts as it brakes which makes the braking system feels a lot better than me braking in the Z.

But thanks again for a way to eliminate the master cylinder.


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[Starman]

I?ve had the Goodridge stainless brake lines for 12 years, helped quite a bit with soft pedal. At the time they were pretty reasonable $.


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[max76]

If the rear is full to the top (above max) and the front is low, you need a new master

I have the same problem with my 90 zr1 ... the front tank is in the center and the rear is full ... if I put the correct level, after a few kilometers the rear is higher and the front lower ... the car is braking well (as far as I can understand).
Are there gasket kits to overhaul the master cylinder?

I already have stainless brake tube

[TX '90 ZR1]

I have the same problem with my 90 zr1 ... the front tank is in the center and the rear is full ... if I put the correct level, after a few kilometers the rear is higher and the front lower ... the car is braking well (as far as I can understand).
Are there gasket kits to overhaul the master cylinder?

I already have stainless brake tube

Max,
Steve from Crossed Flag Performance and I have been trying to locate an overhaul kit for a while. There used to be a kit available, but there are none to be located at this time as best we can tell.
There are some replacement master cylinders available, but they are not visually the same as the original.
Only choice appears to be to replace with an aftermarket unit and keep your original to overhaul if someone comes up with a way to do it.
If someone has found a solution, maybe they will chime in. I know a few of us would love to find the solution.
:cheers:

[max76]

Max,
Steve from Crossed Flag Performance and I have been trying to locate an overhaul kit for a while. There used to be a kit available, but there are none to be located at this time as best we can tell.
There are some replacement master cylinders available, but they are not visually the same as the original.
Only choice appears to be to replace with an aftermarket unit and keep your original to overhaul if someone comes up with a way to do it.
If someone has found a solution, maybe they will chime in. I know a few of us would love to find the solution.
:cheers:

Hello....
this is what i think you are searching for:

https://www.ebay.it/itm/172512514733?&_trksid=p2380057.m570.l47448&_trkparms=gh1g%3DI172512514733.N59.S1.typeSellerIn itiatedOffer.R1.TR2&ul_noapp=true&autorefresh=true

It's incredible that isn't there any replacement kit for this kind of master cylinder....The PBR Factory doesn't exist anymore??

I also read on other forum the quality of aftermarket master cylinder is not very good...after 6/7 years they replace agayn the M/C....is it true? Is there a brand better than another? Suggestions??