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Front brakes dragging WB caliper

Started by _GTRXU1Rooster_ , Mar 10 2011 09:22 PM

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#1 _GTRXU1Rooster_

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Posted 10 March 2011 - 09:22 PM

Gday all I am having issues,I have a LC Torana with HX Stub Axles, brand new HX Rotors (25.4mm thick) WB Alloy Calipers with new pads also, XU1 brake booster and LX Torana master.the problem I am having is when I pump the brakes up then release the pedal the brakes are dragging to the point to turn the rotor you need 2 hands....

the Booster has been completely rebuilt , with a longer push rod to suit the different master,

The Master just got resleaved and completely rebuilt just the other day.

The HX Stub axles are swapped left to right.

The calipers have been rebuilt and have been tested by the brake dude, and retracts properly apparently. The slides are working also fine, and have been ground down to suit the swap from left to right.

The Proportional Valve has been out and works fine aswell.... nothing stopping it from moving fluid thru.

now the drama I am having is that the brakes are staying on and I cant figure out why. I drag raced my car and on the return track I had to pull over because I couldnt see a thing with all the brake smoke. Up on stands the brakes are applied and can not be turned, release the pedal and it takes two hands to turn the rotor..... a screw driver in the caliper and its easy to open them back up and the rotor spins freely again.running out of options these days with it... new brake lines maybe? its only the fronts sticking that I can tell, Any direction would be appreciated.

Clay

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#2 S pack

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Posted 10 March 2011 - 11:18 PM

Your problem is most likely the length of the brake booster pushrod going into the master cylinder is too long and is keeping the brakes applied to some extent.
Or your master cylinder could be faulty even though it has been sleeved and kitted.
Or a drum brake check valve has been installed in the front brake line port of the master cylinder, disc brakes should not have a check valve installed in the port.

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#3 dattoman

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Posted 11 March 2011 - 02:14 AM

s above

When it locks up... undo the master and pull it forward off the booster and see if it releases... if it does... the clearance is wrong
If it doesn't... check the line pressure valve is not fitted to the front brake circuit

The fronts should be plumbed to the smaller port out of the master

LX masters changed half way thru... wonder which one you have

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#4 _GTRXU1Rooster_

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Posted 11 March 2011 - 08:06 AM

s above

When it locks up... undo the master and pull it forward off the booster and see if it releases... if it does... the clearance is wrong
If it doesn't... check the line pressure valve is not fitted to the front brake circuit

The fronts should be plumbed to the smaller port out of the master

LX masters changed half way thru... wonder which one you have

yeah its definately not the booster, I got the brakes pressured up so they were dragging again and then moved the master clear from the booster completely and they stayed on no change at all.... which eliminated the booster, so how do I go about testing the master then? should I take it back to the brake guys who built it?

Cheers guys

Clay

Edited by GTRXU1Rooster, 11 March 2011 - 08:09 AM.

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#5 _Ozzie Picker_

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Posted 11 March 2011 - 12:18 PM

is it both rotors? had a friend with same problem on 1 wheel,flexable hose had shit it self,let fluid past but would not return.

i have found MOST cars need 2 hands to rotate the disc only,and its hard to do.

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#6 _GTRXU1Rooster_

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Posted 11 March 2011 - 12:32 PM

is it both rotors? had a friend with same problem on 1 wheel,flexable hose had shit it self,let fluid past but would not return.

i have found MOST cars need 2 hands to rotate the disc only,and its hard to do.

yep its both rotors, and it drags enough for the brakes to fill the cab with smoke by the end of a 1/4 mile race at the strip... but its on too much....

Clay

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#7 _Ozzie Picker_

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Posted 11 March 2011 - 12:49 PM

maybe something went wrong with the caliper rebuild,

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#8 _Quagmire_

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Posted 11 March 2011 - 02:26 PM

try bleeding it again
and free your pistons while your there
with a clamp
just in case
you checked the check valve as datto suggested?

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#9 dattoman

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Posted 11 March 2011 - 02:42 PM

What master is on it ????????

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#10 _GTRXU1Rooster_

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Posted 11 March 2011 - 06:20 PM

this is the Master that I am using on it.....

Attached Files

Master 1.JPG 1.4MB 8 downloads
Master 2.JPG 1.51MB 1 downloads

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#11 dattoman

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Posted 11 March 2011 - 06:25 PM

Is the large outlet going to the rear brakes ?

And whats the # stamped on the end

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#12 _GTRXU1Rooster_

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Posted 11 March 2011 - 06:31 PM

Is the large outlet going to the rear brakes ?

And whats the # stamped on the end

the largest port is the front one (holds more fluid that is) is going to the front calipers

the number on the front is P 210

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#13 dattoman

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Posted 11 March 2011 - 06:34 PM

P7210

And the large port...as in size of hole... not part of cylinder... where the outlet is !!!!

Thats rear brakes ....... if you have it plumbed the other way... the valve is not in the front... hence holding on

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#14 _GTRXU1Rooster_

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Posted 11 March 2011 - 06:40 PM

No, then the larger port then using the larger flare nut (the one that isnt rusty looking) is the rear, and that goes to the rear brakes also, the newer looking one is smaller and is going to the front brakes, you mentioned a valve in the master, to check for it, do I pull the front hose off the master and check for it? am I looking for a brass restrictor?

Clay

Edited by GTRXU1Rooster, 11 March 2011 - 06:41 PM.

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#15 Collo

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Posted 11 March 2011 - 06:42 PM

Looking at the pics, the lines are round the wrong way. It looks like Datto is on the money. As usual :spoton:

No, then the larger port then using the larger flare nut (the one that isnt rusty looking) is the rear, and that goes to the rear brakes also, the newer looking one is smaller and is going to the front brakes, you mentioned a valve in the master, to check for it, do I pull the front hose off the master and check for it? am I looking for a brass restrictor?

Clay

Larger port is for the front brake line, regardless of reservoir size.

Edited by slr_v8, 11 March 2011 - 06:41 PM.

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#16 _GTRXU1Rooster_

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Posted 11 March 2011 - 06:58 PM

so the larger Flare Nut then is for the front calipers then? that could solve my issues then hopefully

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#17 Collo

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Posted 11 March 2011 - 07:22 PM

Noooo just checked mine and misread datto's post. Go with him he's the guru.

Sorry for any confusion, I'll leave now.

Edited by slr_v8, 11 March 2011 - 07:23 PM.

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#18 _GTRXU1Rooster_

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Posted 11 March 2011 - 07:27 PM

ok then, from the first picture then;

the Rusty looking flare nut (1/2') is for the fronts, and

the cleaner zinc looking flare nut (9/16') is for the rears correct?

clay

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#19 Collo

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Posted 11 March 2011 - 07:33 PM

Yep 1/2' front, 9/16' rear. Resevoir size doesn't matter. I went through this with my LC when I sorted the brakes out.

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#20 _GTRXU1Rooster_

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Posted 11 March 2011 - 07:36 PM

well it looks like the hoses are around the right way then.... bugger I thought I had a result then.....

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#21 Collo

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Posted 11 March 2011 - 07:42 PM

Yeah sorry bout that mate.

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#22 _GTRXU1Rooster_

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Posted 11 March 2011 - 08:31 PM

any other ideas why it could be the way it is? what about the rubber hoses? if they were to collapse inside would that stop it for returning perhaps?

I have a mate coming over next week sometime with his HX so we can pull of individual parts and test them one at a time on mine or his to see if mine works or his fails with mine on it....

Clay

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#23 S pack

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Posted 12 March 2011 - 12:01 AM

any other ideas why it could be the way it is? what about the rubber hoses? if they were to collapse inside would that stop it for returning perhaps?

I have a mate coming over next week sometime with his HX so we can pull of individual parts and test them one at a time on mine or his to see if mine works or his fails with mine on it....

Clay

G/day Clay

The check valve (little black plastic thing and a spring) that Datto and I mentioned is located in the brake line port behind the brass seat that the brake line flare seats against in the master cylinder. Drum brakes need them but Discs don't. Hence one should be fitted under the port seat for the rear brakes (if drums are fitted) only.

Easiest way to check is disconnect the front brake line from the master cyl and insert a piece of wire into the hole in the brass seat. If the wire will not go in easily more than 1/4" then there is a check valve fitted. If the wire easily disappears into the port 3/8" to 1/2" then no check valve is fitted and is correct for Disc brakes.

I could be wrong and probably am but I believe your problem lies with the pistons and cups inside the master cylinder.

Cheers
Dave

Edited by S pack, 12 March 2011 - 12:01 AM.

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#24 _GTRXU1Rooster_

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Posted 15 March 2011 - 06:58 PM

http://www.gmh-toran...-powerful-rb30/

this is my car here.... still having the same issues, mate is coming over tomorrow with his HX kingswood and we are going to chuck his master on and see if that changes anything, and mine onto his, and maybe if that changes nothing my calipers onto his car too

Clay

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#25 _GTRXU1Rooster_

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Posted 03 April 2011 - 09:47 AM

Alrighty,

Yesterday arvo mate came round with his HX Kingswood, with disc/drum setup, chucked his master on to start with, it was the back to front facing one but the front hose goes to the front ofthe proportional valve same as the way mine was, fitted it up same as it was on his car and same problem brakes holding on. then chucked his proportional valve on and once again nothing changed.

So this tells me that

Master not the problem
Proportioning Valve not the problem
Calipers not the problem

So could it be the Rubber hoses or even the metal hoses? Like the hoses collapsing under vacuum, if it were them I would have thought that days later the fluid would have bipassed and returned to normal?

Any ideas?

Clay