Author Topic: Brake problem, 70 Challenger  (Read 4892 times)

Offline Jeffs 70 RT

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Brake problem, 70 Challenger
« on: July 10, 2010 - 07:56:14 AM »
Hello everyone! Maybe someone can give me an idea where to go with this...1970 Challenger. Everything brake wise is new. All new stainless lines, new brake valves from Inline Tube. New master cylinder from Just Right, all new calipers, cyls, hoses etc. Started this bleeding process couple weeks ago. I could only get fluid to the right front. I tried gravity bleeding and having a helper pump.....nothing! Pedal feels fairly firm, so I figure a restriction in one of the valves. Ordered new valves from Inline, exact same problem. Pedal feels fairly firm, doesn't drop when I take the bleeder screws out. I've never had so many problems with a car! Getting frustrated!! Take care,  Jeff




Offline Bullitt-

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Re: Brake problem, 70 Challenger
« Reply #1 on: July 10, 2010 - 08:22:17 AM »
I have not had this problem but speculate that it may have to do with the proportioning valve... In the service manual it suggests "holding the valve open" in reference to the round piece to the left of this picture on the distribution block, this is found at other locations on combination valves.     I'd also guess you may need to bench bleed the master cylinder better or it's bad.

Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
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Offline somedaysoon

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Re: Brake problem, 70 Challenger
« Reply #2 on: July 10, 2010 - 11:07:30 AM »
 I'm no expert but if the pedal won't drop when you open the bleeder then you have something restricting the flow.  I think that's where I would start. I think I would first run a couple lines straight up back into the master just like bench bleeding and make sure it is pushing fluid. Then maybe undo each line one at a time and see if you can push fluid  through and see what happens, and when I say each line I mean maybe disconnect at the metering block first and then every join t down the line until you find it. Oh and be careful not to blow fluid all over. Pete
« Last Edit: July 10, 2010 - 11:10:52 AM by somedaysoon »

Offline Chryco Psycho

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Re: Brake problem, 70 Challenger
« Reply #3 on: July 10, 2010 - 08:34:59 PM »
the hose couldbe collapsed internally too

Challenger - You`ll wish You Hadn`t

Offline high perf mopar

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Re: Brake problem, 70 Challenger
« Reply #4 on: July 10, 2010 - 08:37:01 PM »
do yourself a favor if your not concerned about o.e.m. looking brake prop valves and do whats in the link provided..http://www.cuda-challenger.com/cc/index.php?topic=66387.60 .i had the same problems,,i was eventually able to bleed all 4 corners but they never worked right..rears would not work at all.and this is not my first chicken bbq..

i left everything stock except the prop valve which is wilwood,,now they work great,,was able to take it around the block today for the 1st time after almost a years work,,the brakes were holding me up..and because the valves adjustable with 2 separate fluid systems alot safer.
1971 barracuda
440-6 shaker
chrysler 3x2 competiton carbs mech,what chrysler should have done.
b-5 blue
"you got yourself some motor there boy!" 1973,,white lightning.MGM studios burt reynolds

Offline Jeffs 70 RT

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Re: Brake problem, 70 Challenger
« Reply #5 on: July 12, 2010 - 09:35:15 PM »
Thanks for the reply's! Question about the Wilwood valve. Is this on a 1970? Did you just do away with the 2 valves that are factory? And, what application is the alumn master cylinder from? I've seen a few of these used. I would like to keep everything original, but I would also like to be able to DRIVE this summer too! Thanks again! Jeff

Offline Chryco Psycho

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Re: Brake problem, 70 Challenger
« Reply #6 on: July 13, 2010 - 12:24:21 PM »
the Wilwood valve just goes in the line to the rear brakes & limits the pressure to the rear , the factory valves are deleted this way .
 did you bleed the master before attaching it to the car ?

Challenger - You`ll wish You Hadn`t

Offline Jeffs 70 RT

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Re: Brake problem, 70 Challenger
« Reply #7 on: July 13, 2010 - 12:37:42 PM »
Hey guy's! Yes, I bled the master a couple times. Had good flow from both lines. I've ordered the Wilwood valve from Summit. What about the alumn master that some are using? What application did this come from? My master has the 4 bolt attaching. All the alumn masters I've seen are just 2. Is there an adapter to be used? Thanks again everyone! Jeff

Offline Chryco Psycho

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Re: Brake problem, 70 Challenger
« Reply #8 on: July 13, 2010 - 01:03:49 PM »
the alum master was used in the 80s & yes it reqiuers an adapter plate to use it , I think Mancinis sell the adapter

Challenger - You`ll wish You Hadn`t

Offline brads70

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Re: Brake problem, 70 Challenger
« Reply #9 on: July 13, 2010 - 06:58:35 PM »
Thanks for the reply's! Question about the Wilwood valve. Is this on a 1970? Did you just do away with the 2 valves that are factory? And, what application is the alumn master cylinder from? I've seen a few of these used. I would like to keep everything original, but I would also like to be able to DRIVE this summer too! Thanks again! Jeff

Yep mine is a 1970. I removed the stock p-valve and installed the Wilwood in it's place. I also used different rear wheel cylinders too as was suggested on that post. I also am using the big brake set up on the front.  I bought the master from Dr.Diff on E-bay.
Brad
1970 Challenger 451stroker/4L60 auto OD
Barrie,Ontario,Canada
Proud to own one of the best cars ever made!!!!!

My restoration thread 
http://www.cuda-challenger.com/cc/index.php?topic=59072.0
 My handling upgrade post
http://www.cuda-challenger.com/cc/index.php?topic=73985.0

Offline high perf mopar

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Re: Brake problem, 70 Challenger
« Reply #10 on: July 13, 2010 - 08:36:05 PM »
im using a stock new replacement castiron m/c instead of the aluminum one.so, when one looks at my brake setup it looks stock until you get to the prop valve,,very simple to bleed.as easy as it gets..get some speed bleeders and you'll be done in  20 minutes like i was :bigsmile:
1971 barracuda
440-6 shaker
chrysler 3x2 competiton carbs mech,what chrysler should have done.
b-5 blue
"you got yourself some motor there boy!" 1973,,white lightning.MGM studios burt reynolds

Offline Jeffs 70 RT

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Re: Brake problem, 70 Challenger
« Reply #11 on: July 15, 2010 - 01:31:42 PM »
Hey guy's! Thanks for the help. My alignment tech finally figured this out! Don't rely on memory when hooking everything back up! AND, read the assembly manual! None of which I did! Anyway, I had 2 lines switched. I had the front bore of the master going to the hold-off valve and the line for the LF on the TEE valve. Brake fluid was just not flowing correctly giving me all the problem. I have a Wilwood adjustable valve if any one needs one! Take care! Jeff