switchblade327
11-28-2010, 01:47 PM
Hey guys,
I've been abroad for the better part of a couple of years and am just getting back to my car, which has been slowly worked on in a resto shop for that time. They've gotten a lot done but the car doesn't really start or stop so I'm trying to jump back in and help. This won't be my last question for you guys, I'm sure :)
Anyway, my '55 Bel Air has been switched to 4 wheel discs (had been converted to disc/drum before I bought it) but when test driven (not by me) it barely stopped. They've bled the crap out of the lines and still nothing. There are no apparent leaks so we suspect a mismatch of the components.
The front brakes are a kit from Danchuk, with 13" corvette rotors and PBR calipers like this:
http://www.danchuk.com/ItemForm.aspx?item=12817 I went with it because it was a big disc, good price and many high performance brake kits for tri-fives push the wheels out from stock.
The shop owner was concerned that the calipers of this kit only grab the outer edge of the rotor, like this:
42549
But Danchuk has been selling this kit for years with no complaints about people not being able to stop, and the outer edge is where the most leverage is anyway.
The rears are 12.25" Wilwoods and were done much later when the stock rear axle was swapped to a 9" (hence the total mismatch).
Before I continue, am I crazy to run this combination? In retrospect, 13" Wilwoods in front would've been nice and perform better (and look better behind the wheels though cost twice the price) I'm sure but is this combination at least safe and usable?
The master cylinder is a Corvette disc/disc (not sure what diameter) with booster. The proportioning valve is a nonadjustable GM one, possibly disc/drum.
My thought is that the master cylinder is the most likely culprit. The proportioning valve is probably wrong for this setup and will be changed if incorrect but if I understand (nonadjustable) proportioning valves correctly, neither one would deprive the front brakes of adequate pressure to stop.
With having discs this big, is a stock style disc/disc master cylinder going to cut it or do I need to go aftermarket?
Are the brake lines a potential problem here?
Any recommendations for diagnosing? I have about one month to get as much done as I can on this car before leaving again so I want to attack this problem with a vengeance.
Thanks for any help and sorry for my ignorance. The system is a hodgepodge of my work and the shop's work and on top of that, I'm rusty as hell on my car knowledge.
I've been abroad for the better part of a couple of years and am just getting back to my car, which has been slowly worked on in a resto shop for that time. They've gotten a lot done but the car doesn't really start or stop so I'm trying to jump back in and help. This won't be my last question for you guys, I'm sure :)
Anyway, my '55 Bel Air has been switched to 4 wheel discs (had been converted to disc/drum before I bought it) but when test driven (not by me) it barely stopped. They've bled the crap out of the lines and still nothing. There are no apparent leaks so we suspect a mismatch of the components.
The front brakes are a kit from Danchuk, with 13" corvette rotors and PBR calipers like this:
http://www.danchuk.com/ItemForm.aspx?item=12817 I went with it because it was a big disc, good price and many high performance brake kits for tri-fives push the wheels out from stock.
The shop owner was concerned that the calipers of this kit only grab the outer edge of the rotor, like this:
42549
But Danchuk has been selling this kit for years with no complaints about people not being able to stop, and the outer edge is where the most leverage is anyway.
The rears are 12.25" Wilwoods and were done much later when the stock rear axle was swapped to a 9" (hence the total mismatch).
Before I continue, am I crazy to run this combination? In retrospect, 13" Wilwoods in front would've been nice and perform better (and look better behind the wheels though cost twice the price) I'm sure but is this combination at least safe and usable?
The master cylinder is a Corvette disc/disc (not sure what diameter) with booster. The proportioning valve is a nonadjustable GM one, possibly disc/drum.
My thought is that the master cylinder is the most likely culprit. The proportioning valve is probably wrong for this setup and will be changed if incorrect but if I understand (nonadjustable) proportioning valves correctly, neither one would deprive the front brakes of adequate pressure to stop.
With having discs this big, is a stock style disc/disc master cylinder going to cut it or do I need to go aftermarket?
Are the brake lines a potential problem here?
Any recommendations for diagnosing? I have about one month to get as much done as I can on this car before leaving again so I want to attack this problem with a vengeance.
Thanks for any help and sorry for my ignorance. The system is a hodgepodge of my work and the shop's work and on top of that, I'm rusty as hell on my car knowledge.