Topic: calipers/brake lines
in Forum: C3 Engines, Driveline and Handling
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Lifetime MemberEquinunk, PA - USA
Joined: 10/31/2007
Posts: 2475
Vette(s): 1972 conv, 4-speed, 350, 200hp, numbers match, rally wheels, war bonnett yellow w/white top. good condition, nice driver.
Good Morning, I am not familier with the rear calipers on my 72'. I am replacing the crossover line for the brakes. I notice there are two bleeders on each one. Is there a sequence to which one to bleed first? Thanks. Also, becouse this car does not have power brakes, are they usually a little more difficult to stop? I have noticed the crossover line is crushed, and think this may be why it stops/slows sub standard. Any other advice would be helpful.
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As for inside or outside, I recall the books recommend inside first, but I just did mine yesterday and I went back and forth several times to be sure I got all the air out.
Joel (Adam's Apple) says to do the outside first.
Mine is an '82 and I actually have three bleeders on each rear caliper, so I bled all three. I had a lot of air in the rears. Not much in the fronts.
As for the crushed line, I agree to replace it.
Then bleed the brakes.
I used a vacuum pump so I could bleed them without an assistant. Didn't need to cover the reservoir either, so it was easy to check the level and refill when necessary.
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Do you think it makes a difference if you are pressure bleeding or vacuum bleeding?
When I did the rears I had a lot of air, so I did both wheels several times until I was confident it was all out.
And on each caliper I did inner and outer several times.
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Pressure bleeding is better. Vacuum bleeding sometimes will cause air to draw into the calipers through the seals. If the calipers are o-ring style, they won't suck air during vacuum bleeding.
So just enough vacuum to draw the oil out without sucking air past the pistons.
Ken, If I do use the vacuum pump, should I do the fronts first like the instructions on the pump say or the rears like the Vette manuals say?
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I have used both and I like the pressure bleeder the best. The lines to the back brakes make it take a lot longer but with the pressure bleeder it was much faster then the vacuum bleeder. Just make sure you don't let the fluid run out or you will have to start all over. Some people say you can gravity bleed them but i could never get mine to work.
Brian - NCM Lifetime Member
73 coupe L48, Flat-top pistons, Performer RPM Heads, Crane Cam and roller rockers, Holley 650 vac sec. Performer intake,
3.55 gear BTO 200-4R trans,
Leather seats, Seatbelt Plus 3point seatbelts, Pioneer CD player
Magnaflow Exhuast System
Dewitt radiator and dual electric fans
Borgeson Steering box
I would do the rear first, like the manual says. But either way will work.
After I go around the car, I always go around a second time.
If you have a problem with the vacuum bleeder sucking air, just finish off by manual bleeding with a helper pumping the brakes.
Mark,
if you are replacing one line, then replace them all. I only replaced one (besides the opposite advice from here) and I now regret it since I have to go back and do it again.
I rebuilt the calipers so I started with an empty cylinder. As Dave said, make sure you don't dry it up (I did that!!!).
For the order, I don't think it's so much so about a given sequence, it's about starting from the farthest bleeder from the cylinder and work backward towards the closest. I started with the rear/inner.
Like Ken mentionned, I also used a helper to get things started (for pushing the calipers pistons tight before bleeding. I too went around twice.
And btw; try not to mix the type of fluids in case you don't know exactly what is currently in your master cylinder. I had the nice surprise of having both the purple and yellow (one is lighter than the other so when mixed, one will float on top of the other).
If you are colorblind, you can also diffenciate them by the taste.
if you are replacing one line, then replace them all. I only replaced one (besides the opposite advice from here) and I now regret it since I have to go back and do it again.
I rebuilt the calipers so I started with an empty cylinder. As Dave said, make sure you don't dry it up (I did that!!!).
For the order, I don't think it's so much so about a given sequence, it's about starting from the farthest bleeder from the cylinder and work backward towards the closest. I started with the rear/inner.
Like Ken mentionned, I also used a helper to get things started (for pushing the calipers pistons tight before bleeding. I too went around twice.
And btw; try not to mix the type of fluids in case you don't know exactly what is currently in your master cylinder. I had the nice surprise of having both the purple and yellow (one is lighter than the other so when mixed, one will float on top of the other).
If you are colorblind, you can also diffenciate them by the taste.
in Forum: C3 Engines, Driveline and Handling
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