C4 91 Brake Problem
Thread Starter
Racer
Joined: Dec 2003
Posts: 349
Likes: 0
From: Hong Kong
C4 91 Brake Problem
Hi
On my 91, after some rough driving, or even downhill for a while, the pedal travel varies quite a bit. By the time the brakes are hot, the pedal sometimes travels all the way to the floor. Have replaced the master cylinder already, that did no good, same problem still exists.
Any suggestions?
On my 91, after some rough driving, or even downhill for a while, the pedal travel varies quite a bit. By the time the brakes are hot, the pedal sometimes travels all the way to the floor. Have replaced the master cylinder already, that did no good, same problem still exists.
Any suggestions?
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: C4 91 Brake Problem (dailo)
Replace the barke fluid; it's hydroscopic and the water that it picks up over time will boil in high heat causing a loss of pedal height..or worse.
Le Mans Master
Joined: Jan 2000
Posts: 6,374
Likes: 21
From: Traverse City MI
Re: C4 91 Brake Problem (dailo)
Are these the "base" brakes? They have a tendency to fade quite a bit. Are you using OEM pads and rotors? Also, whats the condition of your rubber brake lines?
Thread Starter
Racer
Joined: Dec 2003
Posts: 349
Likes: 0
From: Hong Kong
Re: C4 91 Brake Problem (Aaron71771)
Hi Aaron
I dont know about the rubber lines? could this be causing a problem?
As for the fade, its not really faded, because I have full braking power back if I pump the brakes and pressure returns.
Thanks
I dont know about the rubber lines? could this be causing a problem?
As for the fade, its not really faded, because I have full braking power back if I pump the brakes and pressure returns.
Thanks
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Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Re: C4 91 Brake Problem (dailo)
If the hoses are original, it might be a good idea to replace them. The lining inside the hose will become soft over time and when you apply the brakes, the lining inside will expand which effectively reduces the pressure in the system and you will feel the brake pedal go down further than normal.
Some brake fluids do not handle heat as well as others. The C4 brake fluid has to be a minimum of DOT3 (US standard) and DOT4 fluid is even better in its ability to handle heat from heavy braking. Do not use a DOT5 (silicone based fluid) in ABS-equipped cars.
What condition are the pads in?? If you have new pads, then I would suspect the lines. Figure about $120 for replacement stock brake lines (do all 4 lines)or a bit less for the stainless steel braided lines from Goodridge or Earls. One of the Forum vendors should have them available. You would have to ask about shipping to Hong Kong, though.
Some brake fluids do not handle heat as well as others. The C4 brake fluid has to be a minimum of DOT3 (US standard) and DOT4 fluid is even better in its ability to handle heat from heavy braking. Do not use a DOT5 (silicone based fluid) in ABS-equipped cars.
What condition are the pads in?? If you have new pads, then I would suspect the lines. Figure about $120 for replacement stock brake lines (do all 4 lines)or a bit less for the stainless steel braided lines from Goodridge or Earls. One of the Forum vendors should have them available. You would have to ask about shipping to Hong Kong, though.
Thread Starter
Racer
Joined: Dec 2003
Posts: 349
Likes: 0
From: Hong Kong
Re: C4 91 Brake Problem (c4cruiser)
I didnt know you could use Dot 4 in a Dot 3 System.
Are you sure this wont damage the system.
Also MadVet has those stainless steel lines, should I order those?
Are you sure this wont damage the system.
Also MadVet has those stainless steel lines, should I order those?
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Re: C4 91 Brake Problem (dailo)
DOT4 is perfectly good for a replacement fluid. But in order to get the benefit of the higher boiling point of DOT4 fluid, it should be replaced as a complete flush.
Try Summit Racing for Earls Stainless lines. Go to http://www.summitracing.com and enter part number EAR-28A050 for information. Summit charges and additional $24 for international orders. I have Earl's lines on my 87 autocross/track car and they seem to work fine.
Don't know who makes the MAD lines, but they should work too. As with Summit, shipping charges will be higher than the $14 shown. You should also be able to get stock Vette brake lines through any GM dealer.
Try Summit Racing for Earls Stainless lines. Go to http://www.summitracing.com and enter part number EAR-28A050 for information. Summit charges and additional $24 for international orders. I have Earl's lines on my 87 autocross/track car and they seem to work fine.
Don't know who makes the MAD lines, but they should work too. As with Summit, shipping charges will be higher than the $14 shown. You should also be able to get stock Vette brake lines through any GM dealer.
