Author Topic: Weird Brake problem  (Read 6219 times)

Offline anlauto

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Weird Brake problem
« on: August 18, 2016 - 05:57:44 PM »
Was talking to my mechanic today....he has a Mopar in his shop and they can't figure out why the left front wheel locks up when braking....

They properly tested the line pressure at each caliper and they are equal. They swapped flex hoses side-to-side, same with the brake pads themselves...They tried two other sets of calipers....same issue :clueless:

As a last resort he was going to swap the rotors side-to-side but nobody thinks that would make a difference...
Real head scratcher for sure :pullinghair:
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Offline brads70

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Re: Weird Brake problem
« Reply #1 on: August 18, 2016 - 06:54:34 PM »
Spindle or caliper bracket bent?  :dunno:
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Offline Bullitt-

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Re: Weird Brake problem
« Reply #2 on: August 18, 2016 - 07:37:39 PM »
Seeing how everything else has been eliminated I'm thinking there could be a restriction in the hard line going to the right side..
Pressure wouldn't necessarily be effected but volume would if the line was partially collapsed...   
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Offline 734406pk

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Re: Weird Brake problem
« Reply #3 on: August 18, 2016 - 07:39:02 PM »
Yes swap the existing rotors. It may sound crazy, but it's a process of elimination. There is not much else left. Good luck and post results, sounds interesting.
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
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Offline 734406pk

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Re: Weird Brake problem
« Reply #4 on: August 18, 2016 - 07:42:24 PM »
Seeing how everything else has been eliminated I'm thinking there could be a restriction in the hard line going to the right side..
Pressure wouldn't necessarily be effected but volume would if the line was partially collapsed...

 :iagree: If the quick and easy rotor swap doesn't work, then a line restriction would be a likely cause.
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive

Offline rUNCHARGER

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Re: Weird Brake problem
« Reply #5 on: August 18, 2016 - 07:49:41 PM »
I vote for restriction as well. I wouldn't swap the rotors.

Sheldon

Offline Katfish

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Re: Weird Brake problem
« Reply #6 on: August 18, 2016 - 07:58:02 PM »
Distribution block?

Offline anlauto

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Re: Weird Brake problem
« Reply #7 on: August 18, 2016 - 08:37:56 PM »
I'll touch base with him tomorrow again....

But If I understand brakes correctly...The caliper's piston and flex hose and line are all full of fluid...when you press the brake pedal more fluid tries to enter the same area causing pressure....it's not like there's a large open cavity that fluid has to fill...so I'm not certain where the volume of fluid comes into play.... :clueless:
However...I don't know what I'm talking about, and that's why I have a mechanic  :banghead:
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Offline Chryco Psycho

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Re: Weird Brake problem
« Reply #8 on: August 18, 2016 - 08:48:31 PM »
I would swap the rotor the surface could have a grain to it causing it to have more bite in one direction although I doubt this is the issue .
 Are the pistons the same diameter in both calipers  , if not that would cause an inbalance in pressure .
 I doubt it is the metering block if the pressure measures the same at both calipers .

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Offline anlauto

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Re: Weird Brake problem
« Reply #9 on: August 18, 2016 - 09:04:42 PM »
It's one of those two piece distribution blocks with the separate block for the front brakes. He took the second block out and replaced it with a simple "T" fitting to eliminate the possibility of a faulty block, still no difference.

Yes calipers are the same, both with new pistons. They were rebuilt by a very reputable re-builders and even sent back there yesterday to be checked again....they operate as they should according to them. :pullinghair:

Nobody believes it could be a rotor either.....but the rope is getting pretty short  :banghead: 
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Offline 734406pk

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Re: Weird Brake problem
« Reply #10 on: August 18, 2016 - 09:54:23 PM »
IMO swap rotors passenger side to drivers side and vice versa. Do not introduce a recon rotor, but swap the existing parts. The only expense is labor here. It is the only way to test them.
1973 Challenger 440 6 pack auto 3.91 rear
2012 Dodge Ram 3500 dually 6.7 Cummins Fleece EFI Live
1973 Challenger 318 2bbl auto 2.73 rear 22.5 mpg RIP
1970 Challenger TA 340 4bbl auto-Sold and sad
1999 Dodge Ram 3500 dually 5.9 Cummins Fleece tuned VGT-sold
1995 Kawasaki ZX1100E & still alive

Offline anlauto

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Re: Weird Brake problem
« Reply #11 on: August 18, 2016 - 09:59:34 PM »
IMO swap rotors passenger side to drivers side and vice versa. Do not introduce a recon rotor, but swap the existing parts. The only expense is labor here. It is the only way to test them.

Yup...that's tomorrow's plan I believe...
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Offline jimynick

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Re: Weird Brake problem
« Reply #12 on: August 18, 2016 - 10:25:24 PM »
I'd power bleed the lines again, especially the fronts. There may be a wee bubble in the right side that compresses rather then pushing the piston. Failing that, I'd try another caliper just to eliminate variables. Failing THAT, it's a bit of try and see, but if you crimp the lft frt hard line with a nice pair of side cutters just right, you will balance them out. See, simple, eh? Kinda like me.  ;)

Offline anlauto

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Re: Weird Brake problem
« Reply #13 on: August 18, 2016 - 10:28:30 PM »
That would be as 'bout as redneck as you could get :smilielol:
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Offline Chryco Psycho

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Re: Weird Brake problem
« Reply #14 on: August 18, 2016 - 10:58:19 PM »
Vice grips will work too by reducing pressure to the left front  :bigsmile:

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