ive tried to find the answer myself with no luck ........ 1976 lx torana aftermarket master / proportioning valve and disk / disk setup ..... master is 1inch .......i supposably have a disk / disk prop valve but have a low pedal great braking but i hate the free travel ....... my question is what is the internal differences between disk / drum and disk / disk ....... i have both but one has a removable front plug .....( supposed to be disk / drum ) and the disk / disk only has removeable fitting for rear brake line. ive searched online and have two trains of thought and both relate to the disk / drum prop valve ...... one theory is to increase the spring pressure in the front ..... theory no 2 is to take out the piston in the rear part of the prop valve ...... im confused to what the correct answer is ...... any help would be appreciated
proportioning / combination valve
#1
Posted 06 January 2024 - 04:11 PM
#2
Posted 06 January 2024 - 05:09 PM
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#3
Posted 07 January 2024 - 07:24 AM
#4
Posted 07 January 2024 - 07:29 AM
i have removed the master to bench bleed, ive re lubricated all of the caliper slides ...... i dont remember how many times over the last 6 months that i have bled the brakes. but i cant solve the issue of the free travel ....... have vt front disk and vs rear disks .... so im back to the prop valve as its the only part trhat im not sure about ...... all suggestions greatly appreciated
mark
Edited by marko1au, 07 January 2024 - 07:31 AM.
#5
Posted 07 January 2024 - 08:58 AM
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#6
Posted 07 January 2024 - 09:14 AM
Make sure the reaction disc hasn't fallen off inside the booster. Having it missing creates a long pedal.
#7
Posted 07 January 2024 - 11:01 AM
Certainly got a reaction out of me! Had to take the brake booster off and shake it out of the booster ,hours of fun!
#8
Posted 07 January 2024 - 01:03 PM
booster is less than 6 weeks old ....... i had it rebuilt incase it was the issue .......
claysummers ...... i will check the wheel bearings ....... thankyou#9
Posted 07 January 2024 - 02:37 PM
If you have VT calipers on the front then you will need a VT master cylinder as they are a "Fast fill" unit.
The VT master are not just a 1" master cylinder but a 1" that supplies the rears AND a 1 1/4" to supply the fronts.
This is due to the VT having 2 spot calipers requiring more volume of fluid.
The VT calipers will take more of the fluid and pedal travel before you get any effective braking.
Hope this makes sense
#10
Posted 07 January 2024 - 03:34 PM
claysummers ........ bearings are good ........ but again thankyou
#11
Posted 07 January 2024 - 04:38 PM
Edited by marko1au, 07 January 2024 - 04:38 PM.
#12
Posted 07 January 2024 - 08:28 PM
No worries mate.
#13
Posted 08 January 2024 - 09:03 PM
Ok lets go back a step
What master is on the car ?... replaced when fitting the disc rear ?... is its to suit 4wdisc ?
What valve are you using... as its unlikely to be a thing.. .what what did it come off ?
Are you sure they are VT calipers ?... any casting #'s on them ?
Got any pics of setup ?
Yes check the booster to make sure the reaction discs has not fallen out
It is possible to adapt a VT style master... but lets check some other things first
#14
Posted 09 January 2024 - 02:21 PM
master is an aftermarket 1 in bore to suit 4 wheel disks ........ prop/ combination valve also aftermarket to suit 4 wheel disk ..... booster recently re built using commodoe booster to suit torana bolt pattern .... pics to follow and the vt calipers i will take pics of this afternoon and send them to you.
Mark
#16
Posted 09 January 2024 - 09:30 PM
dattoman ....... email sent
First thing I'd do is check the booster pushrod to master clearance
But it may be a displacement issue with that master as mentioned
You can buy a spacer bracket to bolt to H series/Torana booster to take the VT master
https://www.ebay.com...6kAAOSw8HpgSK2u
This may be an option if its a displacement issue... but will need to repipe car (metric fittings)
Have you tried clamping the rubber hoses (all 5 ) to determine you have a good high pedal to start with.... and dropping a clamp at a time to see if the issue points to a particular wheel ?
#17
Posted 10 January 2024 - 11:56 AM
push rod on booster was setup by the booster repairer, i gave him the master to setup correctly. ......... if we are sure we need the vt master ive already been quoted for the re pipeing ......... havnt clamped the rubber hoses yet but will do to confirm the issue ....... thankyou for your assistance ....... will check out the adapter you suggested
#22
Posted 14 January 2024 - 04:48 PM
dattoman
thanks for the information and i feel it is a distibution issue ....... if i have the rear calipers and body hoses clamped i still have the excessive free play ........ if i clamp both front calipers the free play is noticebly less ...... there is approx 8-10 mm difference between clamped and un - clamped front calipers ..... this measurement is taken between the brake light switch bracket and the pedal it self .......im not sure what the difference is at the pedal pad but ill assume probably 50 mm or more
Mark
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