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Unread 06-03-2013, 12:03 PM   #1
ROB03HD
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1982 CJ7 
 
Join Date: Jan 2006
Location: S.A., Texas
Posts: 66
Problems with new brake booster NEED HELP

I replaced my old booster and MC with a new one from morris4x4 part # MBM-PBUJ7486. Im having problems with the rod inside the booster not making contact with the MC.

I took the air out of the MC and now squirts brake fluid out when i pump it manually from behind with a screwdriver. So i mount the MC to the booster and connect the adjustable rod to the pedal and i get nothing, the pedal just pumps. I can hear the vacuum in the booster as it pumps. Its like the rod inside the booster is not making contact with the MC. I adjusted the rod that connects the the pedal all the way down and get the same. I didnt adjust the rod all the way up because by that time i was fustrated and start working on something else.

Do yall think i need to adjust the rod up? Or is there some thing else im over looking.

Thanks

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Unread 06-06-2013, 12:34 PM   #2
ROB03HD
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1982 CJ7 
 
Join Date: Jan 2006
Location: S.A., Texas
Posts: 66
BTTT


Well finally got the booster to to make contact with the MC. Bled all 4 corners but my brake pedel is still super soft and still have no brakes. I tried the vaccuum pump from habor frieght and got new fluid flowing on all corners. But pedal still has no resistance.

All air is out of MC
Calipers are on correct
Not getting good presure any where.


Could it be the proportioning valve?


Im stuck. Have rebuilt motor running like a champ but cant get the brakes to work.

Any help would be great. Thanks
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Unread 06-06-2013, 01:18 PM   #3
zillla
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1975 CJ5 
 
Join Date: May 2009
Location: Wyoming
Posts: 642
Brakes. Gods revenge on jeepers. I have had a few go arounds with my power brakes. Here's what I would do. Take the MC off, you can leave the lones connected, and have someone push on the beake pedal. See if the rod is actually moving. Next If the rod is moving out, I'd put the MC back in place and unhook one brake line and hook your MC bleeder fitting back in and see if fluid comes out when the pedal is pushed. And you did bench bleed the MC I assume before installing.

FWIW if you do not already know, you can gain some pedal by adjusting the fitting on thre rear of the booster where the pedal connects.
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Unread 06-06-2013, 01:48 PM   #4
ROB03HD
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1982 CJ7 
 
Join Date: Jan 2006
Location: S.A., Texas
Posts: 66
Quote:
Originally Posted by zillla View Post
Brakes. Gods revenge on jeepers. I have had a few go arounds with my power brakes. Here's what I would do. Take the MC off, you can leave the lones connected, and have someone push on the beake pedal. See if the rod is actually moving. Next If the rod is moving out, I'd put the MC back in place and unhook one brake line and hook your MC bleeder fitting back in and see if fluid comes out when the pedal is pushed. And you did bench bleed the MC I assume before installing.

FWIW if you do not already know, you can gain some pedal by adjusting the fitting on thre rear of the booster where the pedal connects.
Yes. all that has been done and still nothing. I even cleaned the bleeders cause they all had some grim in them.

Is there something to reset the proportioning valve? I just read something abt start with the RF to reset the valve. Does this method work? I guess thats probly the only thing i havent tried.

Thanks
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Unread 06-06-2013, 02:44 PM   #5
offroadz
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1980 CJ7 
 
Join Date: Mar 2011
Location: chandler, az
Posts: 277
Do you have ANY leaks on the rear drums? How old are the wheel cylinders on the rear shoes?
Prop valve should be straight forward setup. Is this the old valve or a new one? I put a new one on when I did the upgrade. POS new one was aluminum and complete garbage as the threads stripped. I ordered a new one that is BRASS, no regrets.

It took me and my mechanic about 30 mins to bleed the entire system of air and check to see how to wheels stop with the front or rear axle in the air(spun the tires by hand). Lot of adjusting on the rear drums. I also put in new wheel cylinders on the rear as mine were leaking.
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Unread 06-06-2013, 03:55 PM   #6
ROB03HD
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1982 CJ7 
 
Join Date: Jan 2006
Location: S.A., Texas
Posts: 66
I havent checked the cyclinders. Ill look at them tonight. So far I replaced the front rotors, rear drums, shoes, brake hoses and the brake booster/MC. Which brass valve did you go with? Something online or did you buy it local?
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Unread 06-06-2013, 07:47 PM   #7
offroadz
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1980 CJ7 
 
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Location: chandler, az
Posts: 277
Quote:
Originally Posted by ROB03HD View Post
I havent checked the cyclinders. Ill look at them tonight. So far I replaced the front rotors, rear drums, shoes, brake hoses and the brake booster/MC. Which brass valve did you go with? Something online or did you buy it local?

ebay or online for the brass version:

Part number.
MBM-PV2K-2

http://www.jeep4x4center.com/disc-dr...bm-pv2k-2.html

I paid about $45.00 on Ebay but lucked out on a seller that had a bad rep for shipping. I actually had to call them up to see what the status was.....

My mechanic talked me out of using the old brass valve and I'm glad he did. Had to wait another week but what's another week when I've been down for about 3 years...
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Unread 06-06-2013, 07:49 PM   #8
offroadz
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Location: chandler, az
Posts: 277
Quote:
Originally Posted by ROB03HD View Post
I havent checked the cyclinders. Ill look at them tonight. So far I replaced the front rotors, rear drums, shoes, brake hoses and the brake booster/MC. Which brass valve did you go with? Something online or did you buy it local?
I think the right and left wheel cylinders were like $15.00 a piece. worth it imo if you know how to change them out. Not sure if that came with your rear drums or not(kit?)
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