'73 need brake troubleshooting help
Thread Starter
Burning Brakes
Joined: Aug 2002
Posts: 926
Likes: 2
From: chandler az
'73 need brake troubleshooting help
I replaced the calipers and hoses. I also replaced the master cylinder with a rebuilt. I am not happy with the pedal feel. when the cap is off of the master cylinder - is it normal for a fountain of brake fluid to shoot up? It only seems to do it on the front part of the resevoir and not the rear.
Second part - Is there a replacement proportioning valve available? The car previously sat for 22 years - and I am guessing that it is probably in need of replacement.
Second part - Is there a replacement proportioning valve available? The car previously sat for 22 years - and I am guessing that it is probably in need of replacement.
Race Director
Joined: Feb 1999
Posts: 19,659
Likes: 34
From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
Re: '73 need brake troubleshooting help (brookman)
When you have the cap off the master cylinder, brake fluid will do exactly as you describe. Be careful and don't let it get on the paint, it will discolor it.
Tech Contributor
Joined: Aug 1999
Posts: 15,156
Likes: 3,965
From: Connecticut, USA
Re: '73 need brake troubleshooting help (Eddie 70)
Clean off the brake fluid at once or else you have the paint peel off. Don't push the pedal with the cover off - you know why now.
Sounds like you jhave air in the system. Did you bench bleed the M/C? Were the hoses replaced?
Gary
Sounds like you jhave air in the system. Did you bench bleed the M/C? Were the hoses replaced?
Gary
Intermediate
Joined: Oct 2003
Posts: 49
Likes: 0
From: Prince Frederick MD
Re: '73 need brake troubleshooting help (brookman)
I had the same thing happen on my brother's 72. Replaced calipers, hoses, hard lines from the caliper to the tee on the rear and a rebuilt master cylinder. The brakes would not bleed through the rear lines and the pedal was mush unless I pumped it up. Solution: A new master cylinder (a professional mechanic friend told me most rebuilt master cylinders are junk)proportioning valve and new brake lines all the way. Logic: 30 year-old lines and valve were rusted almost shut on the inside. Although the lines looked OK on the outside, non-synthetic brake fluid actually absorbs moisture and leaving the car sit for a number of years allows the lines to rust - sorta like hardened arteries in the human body. Felt it was far better to replace the lines and valve rather than experience brake failure. I also switched to synthetic fluid. Most of the aftermarket suppliers mentioned on the forum have the parts you need.
Heel & Toe
Joined: Jan 2003
Posts: 22
Likes: 0
From: Richmond Hill Ont
Re: '73 need brake troubleshooting help (brookman)
Did you replace rear soft hoses?? They will breakdown and collapse internally and still look good on the outside.Good luck,( get a power bleeder and some help, they can be a pain) :cheers:
Safety Car
Joined: Aug 2001
Posts: 3,683
Likes: 202
From: Waterford Mi
Re: '73 need brake troubleshooting help (mcmac73)
I have used both a Mighty-Vac and a pressure bleeder with good results. Its hard to get the rear to bleed right by gravity or pumping the pedal.
Team Owner
Joined: Sep 2003
Posts: 88,393
Likes: 2
From: eville in
Re: '73 need brake troubleshooting help (redwingvette)
are the cal. bleeders UP , don't laugh saw it again few weeks ago guy had been driving it that way sence june, he thought it was because of using old
rotors
rotors
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Thread Starter
Burning Brakes
Joined: Aug 2002
Posts: 926
Likes: 2
From: chandler az
Re: '73 need brake troubleshooting help (bigvette1)
Did all that . The hoses are new braded stainless. I Think I need to replace the booster now. When I hold my foot on the brake I hear air hissing.
Drifting
Joined: Jan 2002
Posts: 1,645
Likes: 11
From: Schaumburg IL
Re: '73 need brake troubleshooting help (brookman)
If you hear air hissing, it most likely the booster. Heck after 30 years it dries out. HINT - if you decide to replace it, get a quality unit, not the local parts store rebuild. Searcht he forum for tips and how to's on the change. No matter how you cut it, it is a job 1/2.
