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-   -   1970 Manual Brakes (https://www.corvetteforum.com/forums/c3-tech-performance/516397-1970-manual-brakes.html)

bill69 03-18-2003 08:48 AM

1970 Manual Brakes
 
I have a 70 T-Top LS5 with manual brakes. The brakes don't seem to stop very well although the pedal is very firm. I swapped out the fluid over the winter and they improved but still not what I was expecting. I have only had the car a couple of years and it has always been this way so I am not sure if it should stop better. Basically I have to STAND on the brakes to get it to stop quickly. There is no way I could lock up the brakes. I was wondering if this is the performance I should expect from manual brakes? If not, does anyone have some suggestions as where to start. I don't want to add power brakes since the car is original, less the paint. I have already changed the pads twice, once with carbon metallic, and again with asbestos pads. Same results. Someone told me the asbestos pads have more bite. Thanks for any help.

Brettmc 03-18-2003 09:16 AM

Re: 1970 Manual Brakes (bill69)
 
My manual brakes work pretty good. I haven't tried to lock em up but there is plenty of power if I apply some leg to it. I've got the stock type rotors and organic pads. I can't help ya with your problem but here's a ttt.

Brett :thumbs:


[Modified by Brettmc, 8:17 AM 3/18/2003]

LAvetteman 03-18-2003 10:00 AM

Re: 1970 Manual Brakes (bill69)
 
I say take it to some one who can check those brakes for you. Sounds to me like the calipers are not grabing enough. Does it veer to one side when braking? I have manual brakes as well and even with a little air in the line, stopping isn't a problem. These cars have very ample brake systems. Maybe try a different method of bleeding.

Graemeinvette 03-18-2003 10:03 AM

Re: 1970 Manual Brakes (Brettmc)
 
I have manual brakes on mine and they stop pretty well. I take it you have checked for a siezed caliper? Other than that the only thing I can suggest is to rebuild your master cylinder and go from there. Best of luck! :cheers:

Eddie 70 03-18-2003 10:10 AM

Re: 1970 Manual Brakes (Graemeinvette)
 
Welcome to the forum. Hope you will enjoy your time here.
My 70 also has manual brakes. But I feel like they do a pretty good job. I guess we are all spoiled by power brakes any more. The manual do require a little more pedal pressure but do a good job in stopping the car, IMO.

90 droptop 03-18-2003 10:15 AM

Re: 1970 Manual Brakes (Eddie 70)
 
My 70 vert had manual brakes. Your description is how my brakes felt when I bought the car. I bled the brakes and put on a new master cyl. (not in that order) and it cleared up all my brake problems. Unless you really had to get on the brakes hard, they almost felt like power brakes, not bad at all.

Robert N 03-18-2003 10:33 AM

Re: 1970 Manual Brakes (90 droptop)
 
I agree with the above. The only time the brakes feel like manual brakes are when immediately switch vehicles and can really tell the difference or when they need to be "locked up" for a panic stop. Since you changed the fluid and bled the lines, it should be a caliper with a weak piston or 2 (not grabbing well) or a master cylinder problem. The master cylinder will be the easiest to start with.

I replaced all 4 calipers, lines, pads, and the master cylinder. While I could have gotten away with just calipers, replacing the master cylinder later would mean replacing the fluid again.

RMVette 03-18-2003 01:08 PM

Re: 1970 Manual Brakes (bill69)
 
Having to stand on the brakes isn't normal. Mine are manual and stop pretty good even though I have the power brake kit to install. I agree with all of the previous responses but I'd also look to make sure that all of the pistons in the calipers are actually moving. I've had one side stick and the brake wasn't doing all the work that it was suppose to. Also on the last brake job were the rotors resurfaced? They may be galzed and not being as effective. My .02 worth. Good luck! :cheers:

LAvetteman 03-18-2003 01:47 PM

Re: 1970 Manual Brakes (RMVette)
 
I would think a seized piston would cause a veer. Good point about the rotor being glazed.

turtlevette 03-18-2003 02:46 PM

Re: 1970 Manual Brakes (bill69)
 
The pistons fit so loose in the bores i would be very surprised if they could sieze. You probably have the wrong master cylinder for your application. You might have a master cylinder with a larger bore diameter (power brakes) which would require more effort than a smaller bore. Try replacing the master cylinder first.

jim

427V8 03-18-2003 07:38 PM

Re: 1970 Manual Brakes (turtlevette)
 
I agree with the master clyinder. Bubba probably put in one for a power brake car :U

Oh, also get good pads, they help a lot too

bill69 03-19-2003 08:44 AM

Re: 1970 Manual Brakes (427V8)
 
Wow! I was just hoping to get 1 or 2 responses in a couple of days. I got 10 in just a few hours. I would like to thank all of you for your help. Sounds like I need to look at the Master Cylinder first and then the calipers. I am pretty sure all of the calipers work at least to some degree. I won't explain how I know this, just trust me on that one. Anyway I have already placed the order for a Master Cylinder and that's what my weekend will consist of. The real crappy part is my other Vette, a 75 which I drive all the time, just developed some brake problems as well. Will it ever end. Thanks again and I hope I can return the favor.


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