Disc Brake Conversion Problems

[72futuresweet2wd]

I have changed my 69 over to front disc brakes(w/ a conv kit-new parts) and after a master cylinder that was pulling air and a prop valve that was leaking fluid we finally have brakes(replaced both). But now the rear drums lock up every time you hit the brakes WTF? There is very little pedal unless you pump it and after going a little ways there is no pedal again. If anyone has any ideas any thoughts would be appreciated.

Thanks

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1972 2wd Blazer (Project)
1969 Chevy C10 (Driver) http://community.webshots.com/user/69chevytruck
2002 Chevy Trailblazer (Wifes)

[Desert Rat]

You sure you got all the air out of the lines?also i had a problem with brakes dragging,it took forever to find the problem,it was the adjustment on the rod that goes into the master cylinder.

[72futuresweet2wd]

That adjustment was one of the major problems I ran into on this nightmare of a conversion. We again readjusted the rod this morning now it looks like I am going to go ahead and redo the rear brakes one appears to have been leaking and has saturated the the pad.

Thanks

[Desert Rat]

maybe you should post what the kit was or where you got it,so others can make sure to avoid it,im always leary of the aftermarket kits,id rather bolt in a whole crossmamber from a 71 and up,then you know what you got.

[Project1970]

For the record, when I did my front end with the Early Classic disc conversion, I ended up with that same exact problem - lots of lockup - so we gave ECE a call and asked him. He suggested the leaky rear cylinder - lo and behold, it was a leaky rear wheel cylinder.

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Project 1970 - soon to be seen at http://milhouse.treylis.org:81/

[Fast68Chevy]

yes because the axle grease or brake fluid in rear wil make shoes facings grab the drum facing, not lsip like you opwuld think it owuld

also the combo valve centering can be off, IE air in front lines or bad valve, if rear drums shoes are not wet then i would just swap on a 71-87 combo valve,

good luck

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Randy- Lincoln, IL
randy@ccaonline.com 2177353230
*many GM parts bought, traded, or sold -am parting out: '81 Cutlass Supreme Brougham

current fleet: -71 C-10 350/CH465/3.07- basketcase
-84 Z28 5.0L/700R4/3.73 daily driver
-84 Firebird/SE 2.8L/T-5/3.73/engine bad
-82 purple Trans Am, project #2
*Paint is overrated*
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[72futuresweet2wd]

I don't blame the kit much for the my difficulties it was purchased from Early Classic. I have have purchased a few things from them and have no complaints. The leaky rear cylinder was a problem but it has been changed only to find out the master cylinder (2nd one EC sent me)is a screwed up again. I most likely caused some of the problems by not knowing how important the rod adjustment was(I am not sure that it was pointed out in the instruction). I believe the master cylinders were damaged by the rod being to long. As for the porp valve I am not sure what caused its problem. Anyway Wedsnesday I took it to a local shop and they discovered many of the things I couldn't. It will not be ready until Monday and it may well be the most expensive brake job on a 69 c10 in history(I do not know the cost yet). I should have had someone more experienced with braking system help me out. Oh Well WTF I will be driving it home on Monday so there is a bright side.

Thanks

[This message has been edited by 72futuresweet2wd (edited May 04, 2002).]

[bluzman2004]

I installed a conversion kit, too. Mine just included the adapter plates, rotors, calipers, lines, and pads. I kept the same proportioning valve and mastercylinder that was on the truck with the 4 wheel drum setup. It seems everything is fine, but I'm not sure the new disks on the front are engaging. Are the master cylinder and valve usually changed?

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69 Chevy ProStreet, Low and wild. Check it out http://y42.photos.yahoo.com/bluzman2004

[72futuresweet2wd]

bluzman 2004 I am not sure that it is absolutely necessary but I also added a power booster if that makes a difference. I don't have much experience working on brake systems. I thought it would be simple compared to the 2.5/4 drop with new sway bar, spindles, ball joints, shocks, springs, control arm bushings, etc. that I just did. Well I have my blazer to complete and now I know quite a bit more about brakes.

[Andy4639]

Yes you should get a new master cylinder for disc brakes. The difference is fluid cap. for the disc's up front, and no the booster doesn't make any difference. It doesn't know what kind of brakes you have it just knows that it uses vacuum to help push the pedal down.

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Andy
71's Are for ever!!! or 67,68,69,70,72
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