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brake question

Author Topic: brake question  (Read 9422 times)

vince1976

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brake question
« on: September 18, 2013, 05:47:37 PM »
I kept loosing pedal on the trail the other day.  I would either be on a pitch or the front end raised due to climbing rocks and such.  That seemed to be when it happened the most.  The pedal would go all the way to the floor.  It would come back when the truck returned to level.  I have checked all connections and the fluid resevoir is at the same level (full).  I will bleed the brakes when I get a second body.  My concern and question is since I have converted to disc brakes in the rear doI need to chage the proportiong valve since it was originally for Disc/drum.  Any help or other suggestions appreciated.

2001 tj
60 front
14 bolt rear


thanks,Vince

Offline Wingman

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Re: brake question
« Reply #1 on: September 18, 2013, 06:52:15 PM »
If you converted to disc from drum, you need to switch prop valves because of a residual pressure valve inside.

vince1976

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Re: brake question
« Reply #2 on: September 18, 2013, 07:01:57 PM »
Hey Mark,

Would this be the culprit to loose pressure at cetrain times.  Also, do you have any idea of what valve to get?  Also, I have given up on the tire issue as from what I have read there is not much I can do. I have talked to others who have said when the tire folds like mine it is because it is stiff, cold and new.  Hence, why running more air prevents the folding and pulling off the rim.  I bought an expensive set of trailready/swamper fake beadlocks.

Offline smichaelR22

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Re: brake question
« Reply #3 on: September 18, 2013, 07:09:32 PM »
what MC do you have?  stock TJ will not be up to the task with tons. 

if you have brakes and then you dont- id be suspect of loose wheel bearings or deflecting caliper brackets?



regardless of what people say about proportioning valves, they are a hoax in 4x4 rock crawling. 


high speed truway panic stop yes you will want closer to 70/30 braking power front/rear.  off road it doesnt matter. 
572 single seat race buggy
573 Brolite '97 Ranger, '96 backup ranger
1997 ZJ 35's
2014 Ram 4500 Cummins 6 speed 4x4
48' enclosed trailer

vince1976

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Re: brake question
« Reply #4 on: September 18, 2013, 07:22:55 PM »
Yup, Stock TJ cylinder.  And yes the situation is I have brakes and now I do not.  What are my options for converting to a 1 ton cylinder with ease of conversion.  I am pretty sure no bearings are loose.  What do mean by deflecting caliper brackets so I can check on that one.

Thanks

Vince

Offline Spencer

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Re: brake question
« Reply #5 on: September 18, 2013, 07:30:26 PM »
my set up:
ford d60 w/ twin piston calipers
14b with 1/2 chevy disk conversion

stock MC, prop valve, booster. stops awesome offroad. will lock rears on the street.

keep in mine mine had rear disks stock.

MS upgrade is 3/4 ton dodge van. check online/pirate for details....i have one i pulled from a JY you could have.

Offline smichaelR22

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Re: brake question
« Reply #6 on: September 18, 2013, 07:34:16 PM »
big chevy single bore 1 ton fronts take a lot of fluid, 3/4 ton fronts on the rears also do.

have a buddy pump the brakes up, look for anything deflecting

i have seen bad wheel bearings, broken bads, bent brackets, anything thats moving or deflecting under brake pressure is loosing brake volume


572 single seat race buggy
573 Brolite '97 Ranger, '96 backup ranger
1997 ZJ 35's
2014 Ram 4500 Cummins 6 speed 4x4
48' enclosed trailer

vince1976

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Re: brake question
« Reply #7 on: September 18, 2013, 08:13:33 PM »
I will check for deflection.  I appreciate the offer Spencer.  I have no idea when I would be able to catch back up with you.  I should mention I have lost pedal on a hill but got pressure back after pumping the brakes.  Dont know if this matters.
What does the swap to a bigger cylinder involve?
Thanks

Vince

Offline MrMindless

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Re: brake question
« Reply #8 on: September 18, 2013, 09:05:04 PM »
whether pumping makes a difference is very important. Usually if pumping brings things back you've got something moving around that should not be. if it's hill specific I think I'd look for a short brake line that could be tugging on a caliper at full droop and putting it out of square, taking more effort to bring it back into contact. Not sure what else it could be if the res is full.
Michael Maskalans
#571 Last Minute Motorsports
High Miler: 07.5 Ram 6.7 6sp 4x2, ARB, 19.5s
2003 R'Audi Allroad 6sp
Road Block: 98 Dakota 203/205 triple stick, 42" SXs
Dumpbus: 97 Ram 24v P-pumped, RoadRanger 13sp
'87 AMC Eagle Wagon

vince1976

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Re: brake question
« Reply #9 on: September 19, 2013, 08:45:51 AM »
Pumping seems to help.  I will post up when I can have someone actuate the breaks and check for deflection etc.  I just find it odd to loose all pedal, brake light come on and then have pedal come back.  Where is the fluid going when the pedal hits the floor since I do not loose any fluid--odd?

Vince

Offline MrMindless

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Re: brake question
« Reply #10 on: September 19, 2013, 10:14:50 AM »
Something's got to be opening up a caliper and then it takes a pump or two to close it back up.


Tapatalking in traffic
Michael Maskalans
#571 Last Minute Motorsports
High Miler: 07.5 Ram 6.7 6sp 4x2, ARB, 19.5s
2003 R'Audi Allroad 6sp
Road Block: 98 Dakota 203/205 triple stick, 42" SXs
Dumpbus: 97 Ram 24v P-pumped, RoadRanger 13sp
'87 AMC Eagle Wagon

Offline smichaelR22

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Re: brake question
« Reply #11 on: September 19, 2013, 11:49:10 AM »
i have seen shock shafts or steering parts also push on calipers also to intermittently loose volume. 
572 single seat race buggy
573 Brolite '97 Ranger, '96 backup ranger
1997 ZJ 35's
2014 Ram 4500 Cummins 6 speed 4x4
48' enclosed trailer

vince1976

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Re: brake question
« Reply #12 on: September 19, 2013, 06:29:28 PM »
Thanks for the suggestions.  I had a little time to play with the jeep today.  I had it articulated on a small hill and noticed the rear shock tube was contacting the rear caliper.  Dont know if this will cause a defelction and hence a loss of power but that is now fixed via a grinder.  The brakes lock up on the road so do you reccomend an upgrade to a bigger MC.  From what I understand and correct me if I am wrong a bigger MC means less PSI just more fluid correct?  This will give me more pedal also correct?.  I have to say that my pedal stroke is long before actuation (that sound so awful).  Any MCs out there that I can bolt in?
I keep seeing that a 98-2001 durango or 2500 is a good direct swap. 
Thanks

Vince

 

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