brake pedal ratio???
#1
brake pedal ratio???
hi everyone,
been awhile since I posted, many issues with car and working too much, lol. newest issue is my brakes. car had 4 wheel power drums with single res. converted to dual res. 7 inch brake booster from speedway. everything in system was replaced including all the lines. still have drums all around. problem is I barely can stop car, I cant even take it out for a ride. called their tech dept. and they stated brake pedal ratio or booster might be to small?? I have 19 in. vacuum at manifold?? any ideas?? calculated brake pedal ratio and it comes out to 2.6 to 1, they said this is no good, any help would be appreciated. (62 starfire, 394)
been awhile since I posted, many issues with car and working too much, lol. newest issue is my brakes. car had 4 wheel power drums with single res. converted to dual res. 7 inch brake booster from speedway. everything in system was replaced including all the lines. still have drums all around. problem is I barely can stop car, I cant even take it out for a ride. called their tech dept. and they stated brake pedal ratio or booster might be to small?? I have 19 in. vacuum at manifold?? any ideas?? calculated brake pedal ratio and it comes out to 2.6 to 1, they said this is no good, any help would be appreciated. (62 starfire, 394)
#2
Why do people even buy 7" boosters? There must be one thread a month on this very topic.
Is this a single or dual diaphragm booster? A single diaphragm 7" booster is worthless. Manual brakes would be a better choice.
Is this a single or dual diaphragm booster? A single diaphragm 7" booster is worthless. Manual brakes would be a better choice.
#3
You might want to read this thread (though you can ignore the part about the British cars and hydrovac boosters).
#6
The car is a 62 Starfire. The new M/C will have a shallow piston to match the new booster. The old booster needs an M/C with a deep piston. The only readily available dual circuit M/C that would work with the old booster is the 62-66 Caddy unit.
#16
Yes, is it slipping inside the spool on the master cylinder and not pushing it in? I slipped a piece of 3/8 aluminum round stock into the hole on the master cylinder cut to length so as the pedal had a small amount of free play.
#23
hello again,
here's the latest, got the new booster, installed it, does exactly the same thing. Do you guys think the brake pedal ratio ( 2.6 to 1) has anything to do with it??? I doubt it's a bad booster, even though it acts like one.press pedal down, it stays down, again I have good vacuum. help please, i'm at the end of my rope here!!!!
here's the latest, got the new booster, installed it, does exactly the same thing. Do you guys think the brake pedal ratio ( 2.6 to 1) has anything to do with it??? I doubt it's a bad booster, even though it acts like one.press pedal down, it stays down, again I have good vacuum. help please, i'm at the end of my rope here!!!!
#26
Perhaps you should have your original one rebuilt. Theres a place in Oregon called Booster DeweyPowerBooster, I havnt used him but i did talk to him on the phone. I probably will send him my original booster after i get moved. His prices are very reasonable. Just google BoosterDewey.
#27
If the system is bled, I'm going back to my original assumption on the mismatch between the boost and mc. Separate the 2 and see. You don't have to disconnect the lines, just remove the 2 nuts and pull the master forward a bit.
#28
I haven't had a chance to bleed the system again. I hope that's the problem. As for getting the old system rebuilt, it was junk, got rid of it, although I wish I hadn't. What gets me confused is this was already a power brake setup. All I did was install a 2 compartment m/c. and run another line basically. I might be looking for an original setup soon if I can't figure this out.
#30
hi again, just thought I'd post if anyone's still following this. Got the master/ booster from rock auto for 66 caddy. Bolted up , bled and seems to be working fine!! Only issue is pedal a little low, i'll just deal with that, thanks for all your help.
#31
You should be able to adjust the pushrod between the booster and pedal. If there isn't enough travel, they make extensions that screw on.
#33
Time for a little logic.
If you think about the brake pedal geometry, the length of that pushrod is the ONLY thing that governs height of the brake pedal (since you haven't changed anything else). Obviously, you didn't lengthen it enough. If you run out of adjustment, get an extension.
http://leedbrakes.com/i-19296658-pus...-coupling.html
If you think about the brake pedal geometry, the length of that pushrod is the ONLY thing that governs height of the brake pedal (since you haven't changed anything else). Obviously, you didn't lengthen it enough. If you run out of adjustment, get an extension.
http://leedbrakes.com/i-19296658-pus...-coupling.html
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June 4th, 2016 07:15 AM