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Hi everyone,
ive just rebuilt my HQ calipers and XU1 brake booster and have bought a new master cylinder pbr . Now my problem is the brake pedal almost goes to the floor when braking and theres nothing in between the top and only brakes at the bottom.
anyone got any suggestion on how to fit it????
thanks
danny..
LJ Brake Problem
Started by
dannygtrxu1
, Jul 30 2006 06:48 PM
9 replies to this topic
#3
dattoman
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- Name:Neil
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Posted 30 July 2006 - 07:15 PM
OK
First thing
Whats the part # of the master cylinder you bought ?
2nd thing
How far out of the booster does the pushrod come that goes in the back of the master cylinder?
3rd thing
Are the calipers on the correct sides of the car so the bleeders are facing up ?
First thing
Whats the part # of the master cylinder you bought ?
2nd thing
How far out of the booster does the pushrod come that goes in the back of the master cylinder?
3rd thing
Are the calipers on the correct sides of the car so the bleeders are facing up ?
#4
_rorym_
_rorym_
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Posted 30 July 2006 - 07:18 PM
Dont laugh...I put the calipers on the wrong side and I have been doing this for 40 years! Again..thanks Neil...whats this about a front bumper on the race car?...LOL!
R
R
#5
Posted 30 July 2006 - 11:44 PM
sorry its not a pbr ive just looked at the box its a protex and the number on the box is P7369 there is another number 894689 5CC7
only other number i could find on the master was AB-148
yes the calipers are on the right way
also when the car is not running the brake pedal fills ok but when u start the car there is no filling till u almost hit the floor.
danny..
only other number i could find on the master was AB-148
yes the calipers are on the right way
also when the car is not running the brake pedal fills ok but when u start the car there is no filling till u almost hit the floor.
danny..
#6
dattoman
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Do I feel lucky? Well, do ya, punk?
- Name:Neil
- Location:Perth Western Australia
- Car:LX SS , 76 Cadillac , 3 x dattos
- Joined: 04-February 07
Posted 31 July 2006 - 12:22 AM
OK so a P7369
Which was never fitted to anything prior to a HX or mid model LX
So you had to do some plumbing to fit it on?
The ports would have been the wrong way around
Big port to the rear remember
Anyway........ the booster pushrod should come out 25mm past the front of the cannister
If its 8mm its the w0rng master and you need a P6613 and will need to repipe it again
If its less than 8 ..... say 3-4 or its 21 or so then your reaction discs also fallen out and refer the previous thread about this.
Use search function and search for VH2013
Which was never fitted to anything prior to a HX or mid model LX
So you had to do some plumbing to fit it on?
The ports would have been the wrong way around
Big port to the rear remember
Anyway........ the booster pushrod should come out 25mm past the front of the cannister
If its 8mm its the w0rng master and you need a P6613 and will need to repipe it again
If its less than 8 ..... say 3-4 or its 21 or so then your reaction discs also fallen out and refer the previous thread about this.
Use search function and search for VH2013
#7
Posted 31 July 2006 - 06:59 PM
ok the pushrod is 25mm out of the cannister
no i did't have to do any pluming as that was the same master i had on it b 4.
danny..
no i did't have to do any pluming as that was the same master i had on it b 4.
danny..
#8
Posted 31 July 2006 - 08:05 PM
Ok with the P7369 master cylinder the big port goes to the back of the splitter (not sure what its called) which controls the back brake line.
The smaller port hole goes to the front of the splitter which controls the two front brake lines.
This is the set-up I've got at the moment. Is this the way it should be?
Thanks in advance
Danny..
The smaller port hole goes to the front of the splitter which controls the two front brake lines.
This is the set-up I've got at the moment. Is this the way it should be?
Thanks in advance
Danny..
#9
_rorym_
_rorym_
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Posted 31 July 2006 - 08:17 PM
Danny...work with Neil..he will sort it out..My XU1 V8 stops on a dime and tells me when it is about to lock up...Perfect...I get more confident with it every time I get into it.
R
R
#10
dattoman
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Do I feel lucky? Well, do ya, punk?
- Name:Neil
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Posted 01 August 2006 - 12:51 AM
OK so the pushrod is out at the right length
The Master will work as its plumbed up right despite being wrong for the car.
Someone must have swapped it and plumbed it up to suit at some stage
Calipers are on the right side and you have theoretically bled it to death
You need to start looking for where the low pedal is
You need to start clamping flex hoses and discover if its front or rear
Your caliper pistons may be rolling back on the seals when you release the pedal so you can never pump it up
Clamp rear first..... see if anything imporves........ then clamp both fronts
Drop a clamp at a time and isolate the wheel thats causing the issue
Once you know which wheel is the issue you can work towards fixing it
The Master will work as its plumbed up right despite being wrong for the car.
Someone must have swapped it and plumbed it up to suit at some stage
Calipers are on the right side and you have theoretically bled it to death
You need to start looking for where the low pedal is
You need to start clamping flex hoses and discover if its front or rear
Your caliper pistons may be rolling back on the seals when you release the pedal so you can never pump it up
Clamp rear first..... see if anything imporves........ then clamp both fronts
Drop a clamp at a time and isolate the wheel thats causing the issue
Once you know which wheel is the issue you can work towards fixing it
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