Renault R8/10 dual master replacement

manicgt

Member
Fellow Frogger
Joined
Jul 17, 2013
Messages
136
Location
southampton Ontario Canada
I have a friend who installed a Kangoo dual master as a replacement unit into his Manic car . The Kangoo master was listed as a direct replacement for the R8/10 dual circuit unit . How ever after a short trip the 4 wheels are starting to lock up once brakes warm up if left to cool off they work alright again until warmed up again ?? I have my own thoughts on this but would be interested to hear if any others have had similar experiences ?? I did not inspect the car myself since it was a Manic forum question to be resolved and I live 12 hours away from the car .

Any thought would be appreciated !!

stay well

Manic gt


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Hi Manicgt,

Two things, If the flexible brake lines are old, they will be swollen inside and then the pressure with the pedal will force the fluid easily to the calipers because of the leverage you have on the pedal, but when the pedal is released, there is no pressure to return the fluid. The flexible lines acts as a non-return valve.

The other reason is play between the pedal and the piston. The pedal must have a return spring to return it to a stop everytime and then there has to be a small gap between the pedal and piston. The piston must stop against the circlip at the back. It can be checked by removing the dust cover. This will open the small (1mm) hole to allow the fluid to be released back into the reservoir and release the pressure from the caliper.

Regards, Frans.
 
Hi Manicgt,

Two things, If the flexible brake lines are old, they will be swollen inside and then the pressure with the pedal will force the fluid easily to the calipers because of
Owner stated he had all new flex lines had been installed and said that the kangoo in picture above must be for the R8/10 ?? I questioned him if the Kangoo masters where for disc brakes only from what I have seen they also used drum brakes in the rear which means residual check valves in system for the rear wheel cylinders ??
I will pass on the info about proper adjustment but why only when system has been subjected to a few brake stops I would have thought that out of adjustment should have immediate effects ???

Any more thoughts would be appreciated some where out there there must be a solution !!!

thanks for input .

Manic gt
 
Same thought - I wonder whether the Kangoo MC has an internal valve that retains line pressure for rear drum brakes.
 
This is a replacement for the Alpine A110 system (dual master cylinder), bore is about 19 mm, so destined for small calipers (38 & 32mm), or modified combination of 38 & 38, 48 & 32, 48 & 38mm).
 
Owner stated he had all new flex lines had been installed and said that the kangoo in picture above must be for the R8/10 ?? I questioned him if the Kangoo masters where for disc brakes only from what I have seen they also used drum brakes in the rear which means residual check valves in system for the rear wheel cylinders ??
I will pass on the info about proper adjustment but why only when system has been subjected to a few brake stops I would have thought that out of adjustment should have immediate effects ???

Any more thoughts would be appreciated some where out there there must be a solution !!!

thanks for input .

Manic gt
yeah manic I would be dismantling and remove residual line pressure valve which should solve your problem of pressure build up over a few applications and heating up of fluid/pads.obvious push rod adjustment as previously suggested could be checked before removal..... jim
 
We had a similar problem on a Mazda 626 many years ago.

The problem was the brake booster being faulty and as the engine warmed it acted to apply and lock the brakes.

You can easily check by disconnecting the hose to the brake booster from the engine manifold.

The brakes will still work, just need a bit more foot pressure.
 
I am curious if this issue was ever resolved?
I have been thinking for a while to go to a dual circuit master cylinder on my R8 (Gros Brakes) which currently runs a 22mm single master cylinder.
Would this be a 'bolt in fix' by converting single to dual (obviously with some plumbing adjustments to the existing new lines?)
 
I have a dual master cylinder on my 4CV with R10 brakes. I split the systems front and rear. Brakes work quite well, but I have been able to get a set of the “Big Brakes” for the front using early R16 calipers. I have not fitted these yet.

My master is also 22mm from a 70’s BMW and basically bolted on except that it takes 8mm rather than the original 6mm Renault bolts. I had already upgraded this, and also had to make up a new pushrod to suit as well.

I ran new brake lines and fitted a pressure switch to the rear line (Ford Escort?) to operate the brake lights as the BMW master did not have provision for a switch in the end like the original.

Mecaparts do sell a dual master that is a direct fit for an A110, and thus can be retrofitted to R8/10, but I think they were very pricey at around 400 Euro
 
As a update The owner is still trying different options but every time the problem temporally disappears it soon resurfaces again so the brake problem is still not resolve ! Philp the system does not use a master so no need to check a defective master and Allan thanks for the BMW master for a possible upgrade It is good info to have !
I am not personally involved as hands on and actually driving the car because of the distance so it is a slow process in the diagnostic's reading between the lines to come up with a solution .
Again thanks for all the input! when the solution is finally achieved will post back results I think the owner now is considering ordering another master so may take some time for it to arrive and than installed .
Thanks again
Manic GT
 
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As a update The owner is still trying different options but every time the problem temporally disappears it soon resurfaces again so the brake problem is still not resolve ! Philp the system does not use a master so no need to check a defective master and Allan thanks for the BMW master for a possible upgrade It is good info to have !
I am not personally involved as hands on and actually driving the car because of the distance so it is a slow process in the diagnostic's reading between the lines to come up with a solution .
Again thanks for all the input! when the solution is finally achieved will post back results I think the owner now is considering ordering another master so may take some time for it to arrive and than installed .
Thanks again
Manic GT
Why doesn't he pull it apart and have a look at which end valve has been fitted?
 
I have a dual master cylinder on my 4CV with R10 brakes. I split the systems front and rear. Brakes work quite well, but I have been able to get a set of the “Big Brakes” for the front using early R16 calipers. I have not fitted these yet.

My master is also 22mm from a 70’s BMW and basically bolted on except that it takes 8mm rather than the original 6mm Renault bolts. I had already upgraded this, and also had to make up a new pushrod to suit as well.

I ran new brake lines and fitted a pressure switch to the rear line (Ford Escort?) to operate the brake lights as the BMW master did not have provision for a switch in the end like the original.

Mecaparts do sell a dual master that is a direct fit for an A110, and thus can be retrofitted to R8/10, but I think they were very pricey at around 400 Euro
Alan what model of the 1970 BMW I went on line looking for info and looks like several models are listed for different cars but some of them are now difficult to come by as well ??
thanks for info !
Manic gt
 
HAS ANYONE ELSE NOTICED THAT THE , MC PICTURED HAS 3 HOSES ATTACHED ,IM PRESUMING THE COLOURED BUNGS ON THE TOP ARE WEAR THE RESIVOUR SITS ,,THINKING ONE HOSE FOR EACH SIDE FRONT AND ONE FOR THE REARS .THIS CIRCUIT WITH VALVE FOR REAR DRUMS .I WONDER WHICH HOSES HE IS USING FOR REAR DISKS ,PUGS, MAYBE USE ONE OF THE FRONT HOSES FOR THE REAR Discs
 
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Alan what model of the 1970 BMW I went on line looking for info and looks like several models are listed for different cars but some of them are now difficult to come by as well ??
thanks for info !
Manic gt
It was from a 70’s BMW, not a 2002 as they have a 20mm, my best guess is from either a 2000 or more likely a 3.0Si. I did this in 1994 so the memory is hazy. An ATE brand I believe. The spigot was the same diameter as well as the stud pattern matching up.
 
As a up date for the Kangoo master was removed and a new dual circuit master that was the direct replacement was purchased and installed and now seems to be working well ! Not sure why it did not function as advertised whether improper install or it was just not meant to be ?? Again I was not " hands on " involved in the master trouble but from what has been describe if going with the Kangoo master proceed with caution !

Thanks everyone for helping to provide insight !

Manic GT
 
Locking on brakes after a few applications can be one of 3 things that have all been previously mentioned, although not together.

Diagnose - by quick release & re apply any bleed screw when lockup condition is apparent.
Quick squirt occurs & if brakes are now released 1 or 2
1. Drum m/c fitted incorrectly to disc brakes.
Fix - remove residual pressure valve.
2. No brake pedal free travel.
Fix - adjust so there is @ least a mm push rod travel before contact with m/c piston.
3. Internally swollen flex brake line/s.
Only releasing a bleeder screw out board of or associated with that particular flex hose will release brake/s.
 
Locking on brakes after a few applications can be one of 3 things that have all been previously mentioned, although not together.

Diagnose - by quick release & re apply any bleed screw when lockup condition is apparent.
Quick squirt occurs & if brakes are now released 1 or 2
1. Drum m/c fitted incorrectly to disc brakes.
Fix - remove residual pressure valve.
2. No brake pedal free travel.
Fix - adjust so there is @ least a mm push rod travel before contact with m/c piston.
3. Internally swollen flex brake line/s.
Only releasing a bleeder screw out board of or associated with that particular flex hose will release brake/s.
Ringer all sounds good but being 8 hours away and never seen the car in person plus they already changed out the master and seems to be now working I don't think they want to play with it any longer but if it was mine I still would want to know why it dose not work and get to the bottom of it . From the pictures of the master I seen it did not look like residual valves where in it ! so maybe it could have been adjustment of the rod ??

Starting to look like another mystery not solved ???

thanks again
Manic gt .
 
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