LX Master Cylinder lines
#1 _slr253_
Posted 27 December 2007 - 07:47 PM
I'm not sure if my brakes have been setup correctly as the pedal is very soft/spongey. I have only driven my LX a few times in the last 6 months and I have always noticed how bad the brakes feel. It has HQ calipers & rotors up front and VN calipers & rotors at the rear. This is how I bought it.
I've seen photos of LH & LX Toranas on the web and the brake lines from the master cylinder to the proportioning valve are the opposite to mine. I also checked my mum's original LH L32 SL/R and hers has the same setup, but her brakes lock up very easily.
Hopefully the picture below will help.
Cheers,
Brett
#2
Posted 27 December 2007 - 08:30 PM
#3 _rorym_
Posted 27 December 2007 - 09:33 PM
How did I do Datto??
R
#4
Posted 28 December 2007 - 12:30 AM
Pipes are the right way round
#5 _slr253_
Posted 30 December 2007 - 07:37 PM
I'm sorry, but I need a bit more info from your advice.
Rorym: When you say the rear pipe, do you mean pipe on the Master Cylinder, closest to the firewall?
Dattoman: Do you mean when the rear discs went on? Does it matter if the pipes on the Master Cylinder are swapped around?
Please note that I don't know how the proportioning valve works. On Herne's "Tangerine Dream 308", his Master Cylinder pipes are connected to the opposite connections on his proportioning valve, which is why I'm confused about my setup.
Thanks again for your advice.
#6 _Herne_
Posted 30 December 2007 - 08:25 PM
They work very well.
Cheers
Herne
#7
Posted 31 December 2007 - 08:21 PM
#8 _Herne_
Posted 31 December 2007 - 09:16 PM
Cheers
Herne
#9 _SS Hatchback_
Posted 31 December 2007 - 09:41 PM
#10 _Herne_
Posted 31 December 2007 - 11:25 PM
Cheers
Herne
#11 _rorym_
Posted 01 January 2008 - 12:10 AM
Yep.Rorym: When you say the rear pipe, do you mean pipe on the Master Cylinder, closest to the firewall?
R
#12 _rorym_
Posted 01 January 2008 - 12:16 AM
R
#13 _slr253_
Posted 03 January 2008 - 08:10 PM
Rorym: Your picture shows that the larger tank on the master cylinder is at the front while mine is at the rear. Should the larger tank on the master cylinder be used for the front brakes? What difference in braking would it make if the front brakes were on the smaller tank, which is my current setup?
SS Hatchback: What model Commodore should the front of the booster be? I'm assuming that the master cylinder would be of the same model Commodore.
Cheers,
Brett
#14 _SS Hatchback_
Posted 03 January 2008 - 10:20 PM
#15
Posted 08 January 2008 - 01:47 AM
He is feeding the front brake tank of Master cylinder into the rear brake section of the proportioning valve. Anyone else see this?
Dattoman?
You must be locking up the rears?
In reference to PBR Master cylinders used for DISC/DRUM setups, the LH's had the P7210 which had the large tank for the front brakes towards the front as RORYMS pic shows.
Unfortunately as Holden did with a lot of their parts they also used this master cylinder on the first 9 months of LX Torana (till Dec 76).
Then they changed to the P7369 Master cylinder which has the large tank for the front brakes on the back(at the vaccum bosster end) all the way till the UC too.
#16
Posted 08 January 2008 - 01:57 AM
The large nut is the rear
Simple as that
#17
Posted 08 January 2008 - 07:50 AM
On that same topic, did all HQ-HZ PBR alloy master cylinders have the larger flare nut at the rear.
Does that mean when you fit one to an HZ or a late HX, late LX or early UC, that you need to bend the brake pipes to suit (i.e. swap front to rear).
The late larger GM-H cast iron m/cyl, fitted to those models had the larger flare nut at the front.
It's been so long since I fitted one, that I cannot remember.
Dr Terry.
#18
Posted 08 January 2008 - 11:10 AM
Yes agreed at the M/cyl the larger nut 9/16(larger threaded hole) is the rear brakes and the smaller nut 1/2"(smaller threaded hole) is the front brake but I still think SLR253's pipes are wrong way around, how? well I suspect the pipes he has are madeup ones as they dont have the original factory bending and running position and where made with opposite fittings. So they can only be plumbed one way, the wrong way.
Not sure what you mean by one casting ????
I still believe the cambers are different as piston chamber sizes are also different as well as larger tank capacity for front brakes to cater for larger front disc caliper pistons compared to rear.
I also suspect the front brake chamber was switched to the rear of master cyl on the later M/cyls to ensure a mechanicaly direct connection between pushrod. On the older ones the front brake m/cyl piston was pushed under the pressure of the spring from the rear piston.
If this spring was tired or broken or front piston was siezed only rear brakes work. Off course I may be overthinking the issue.
Dr Terry.
I had to bend pipes around to fit reversed later tank m/cyls as well.
Some early HQ or LH have had the older P66xx series which are arent as tall and have smaller capacity tanks but where still a 25.4mm bore.
P7210 & P63xx have front brake tank towards front (smaller 1/2" nut).
P7369 have front brake tank towards rear (smaller 1/2" nut)
Below info is from PBR catalogue:
HQ 07/1971 - 09/1974 DISC/DRUM, WITH MVAC, 25.40 mm P7210
HJ 10/1974 - 12/1976 DISC/DRUM, WITH MVAC, 25.40 mm P7210
HX, HZ 01/1977 - 12/1980 DISC/DRUM, WITH MVAC, HX MODEL, HZ MODEL, 25.40 mm P7369
LH 03/1974 - 02/1976 DISC/DRUM, WITH MVAC, 4 CYL, 6 CYL, 8 CYL, 25.40 mm P7210
LX 03/1976 - 12/1976 DISC/DRUM, WITH MVAC, 4 CYL, 6 CYL, 8 CYL, 25.40 mm P7210
LX 01/1977 - 03/1978 DISC/DRUM, WITH MVAC, 4 CYL, 6 CYL, 8 CYL, 25.40 mm P7369
Edited by fuzzypumper, 08 January 2008 - 11:12 AM.
#19
Posted 08 January 2008 - 03:08 PM
Large to front small to rear
However as a cost saving measure they went with one casting ... cheaper that way
they just drill and tap the outlets as needed
Rear port size is always the larger one
Regardless of bowl size
They are all 1" bore... no differences there
#20
Posted 08 January 2008 - 04:43 PM
Rear nut is not always large for both models, however the large nut is always for the rear brakes and follows the position of the smaller tank.
P7210
P7369
#21
Posted 08 January 2008 - 07:56 PM
Large port rear brakes
Regardless of what the cylinder looks like
#22
Posted 08 January 2008 - 09:12 PM
I just came back from Cruizin car show at Knox Ozone and I did see a few toranas with P7210 Mcyl with the large nut tapped into what I call the the front brake tank which is opposite to the the one I have at home.
I dont know what PBR where thinking ?????????-
#23 _DOG355_
Posted 12 January 2008 - 08:43 AM
#24
Posted 13 January 2008 - 07:09 AM
Hi DOG355.What is the purpose of removing the brass plug from the master for the rear brakes if you have Vn disc's? Just to send more oil to the rear for more braking force?
It's not really a plug, it's an olive. Also you don't remove it & just throw it away.
What you need to do, if converting to discs, is to remove the olive & then remove & discard the little rubber valve insert (& spring) inside & then refit the brass olive. This rubber valve insert is the residual pressure valve & is not required for discs, it's only used for drum brakes.
If the brass olive is not there, the flare at the end of the pipe will have nothing to seat against.
Dr Terry
#25 _DOG355_
Posted 14 January 2008 - 09:52 PM
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