R10 brake master cylinder upgrade
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  1. #1
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    Default R10 brake master cylinder upgrade

    I'm sure this has been talked about before, but here it is again. I have spoken to an automotive engineer about my car and the upgrades I want to make just to make sure the path I'm going down is going to be street legal. Brakes it seems can be a tricky one. I would like dual brake circuits for both safety and the ability to trim the bias.

    Option one, I have read about Brett's conversion using a R5 master cylinder and two VH44s, I already have one VH44 as that was what was already in the car. Brett mentioned that it is very tight and he wouldn't do it again, it could be that bad.

    Option two, the engineer said that if I put a linkage between the pedal and a modern brake servo that is in front of the master cylinder then he would just have to verify that the linkage is strong enough. The problem here is I can't think of a way to get a linkage to work even with two bellcranks, the geometry of the firewall just won't allow having the master cylinder anywhere near the firewall.

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    Option three, I asked about a race style balance bar brake pedal and the issue there is it would need to be tested with involves a closed road, ie. a drag strip or an air strip. I would have to hire the strip, get the car there and pay for the engineers time, this would be very expensive.

    Option four, replace the current pedal bar with a firewalll mounted forward swing version and put the booster on the front firewall inside the boot with a short linkage. I'll have to bounce this idea off the engineer. I could use the pedal box out of an existing street car if I can find one that is suitable.

    Option five, which is not a good one, I have seen a brake servo actuated by a clutch slave cylinder. So the normal brake master cylinder actuates the clutch slave cylinder which in turn actuates the modern brake servo. The advantage is no modification to the current pedal bar but there is now a single point failure in the brake system. Considering it is currently a single brake circuit I don't see this is a major problem if the goal is just to get booster dual circuit brakes. Also not sure how legal this one would be.

    Option six, leave it as it is, single circuit, one VH44 and just add an adjustable proportioning valve for the rear.

    Opinions? Has anyone ever looked into this?

  2. #2
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    In my humble opinion, would approach this in quite a different manner.

    Definitely go for a tandem master and a split system for safety.
    Not so difficult, simply find a suitable unit that physically fits in and has a bore suitable for
    the rest of the system.
    Also replace all brake lines with new steel tubing while you are at it.

    BUT - attack the weakest link - and that has to be the callipers of an R10.
    Simply raising hydraulic pressure with a booster is only going to make things worse
    with callipers sticking, leaking and just plain unreliable.

    It is a lot of work, but look at suitable lightweight modern callipers, discs, brake hoses etc.

    After all, the objective is to stop short, straight and true every time,Non?

  3. #3
    1000+ Posts J-man's Avatar
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    Hi Christian, a lot of people on here swear by the original R10 brake set-up, with the only real down fall being single circuit. The most common and highly recommended modification is to ditch the proportioning valve in the back. These cars tend to have too much braking on the front and will lock the fronts under heavy braking. I'm actually deleting my proportioning valve this week and I've just bought a brass three way junction block from Power Brakes at Gilles Plains. It cost me the princely sum of $22. By the way, brake hoses are cheap there too. They have the specs still to make them up for $37 each. They're very reasonable there, although those are probably trade prices. I'll be able to report back shortly on how much better the valve delete option is.

    Frans used to race his R8 with standard brakes and no booster with great success.
    cheers,

    John

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    Its funny we all have different experiences with what is the same basic car.

    My experience is racing thousands of kms in my first Dauphine which was fitted with basically standard R8/R10 brakes all round. The only modifications I made were a smaller master cylinder (still single circuit) to give me more powerful brakes (you sacrifice travel), custom made brake pads with Mintex linings and finally and most importantly the best racing brake fluid I could find.
    The car had about 120hp at the flywheel and weighed about 750kg all up with fuel.

    I can hoestly say I never had any trouble with the brakes in all the years I raced it. They were well serviced, when doing targa we would check them over every night, but normally every couple of months I would clean and check everything.

    My current R8 which is nearly standard also has standard brakes and provided I use it regularly the brakes perform very well.

    My vote, good brake fluid, good pads and leave them alone.
    Last edited by Ross; 12th March 2014 at 11:38 AM.
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    John (J-man), Do you know the thread size of the 3 way block? I want to buy one but there are a few different sizes available on e-bay and I'm not sure which one will fit.

    Cheer, Henry

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    hi guys,just be careful when you buy the t piece if you are going to retain the standard coupling nuts.most of the t pieces which are readily avalaible only have a shallow female threading.the result is you will only get two or three turns upon tightening.

    cheers brian
    Last edited by potentz; 12th March 2014 at 07:58 PM.

  7. #7
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    There was a modified R8 in Adelaide, now in Melbourne I think, with a servo in the boot operated hydraulically from the standard master cylinder I think. R8 Gordinis had a servo of course but I've honestly never looked to see how they were operated.

    But really, the standard brakes are good if looked after as some have said here. The callipers are fine if clean internally, particularly the bore and the groove for the 'o' ring. Pedal pressures are low for gentle braking if the pistons and callipers are free to move properly.

    I think many of us have thrown out the proportioning valve and found much better braking - just the increased wear rate on rear pads demonstrates they work harder now in my case.

    If you really want to, there are established calliper/rotor options around with the "gros frein" kits from Mecaparts.

    I can't comment on master cylinder options for split systems - just don't know. But, as said somewhere, you'll get the best braking with a 19 mm master cylinder of the standard ones (up to 22 mm).

    Cheers
    JohnW

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  8. #8
    1000+ Posts J-man's Avatar
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    Quote Originally Posted by rubyalpine View Post
    John (J-man), Do you know the thread size of the 3 way block? I want to buy one but there are a few different sizes available on e-bay and I'm not sure which one will fit.

    Cheer, Henry
    Hi Henry,

    The thread size is 3/8. I took my valve into them to make sure they matched the thread with the block. This one is a Girling M703-3. I've attached happy snaps for reference.

    Hi Brian, the thread is very deep on this adaptor block, so should be ok. I'll find out on the weekend hopefully. I'm looking forward to driving the little beast again. It's been sitting in the shed for about a year this time I think.

    R10 brake master cylinder upgrade-imageuploadedbyaussiefrogs1394703004.261292.jpgR10 brake master cylinder upgrade-imageuploadedbyaussiefrogs1394703019.226537.jpg
    R10 brake master cylinder upgrade-brass-union.jpg
    Attached Thumbnails Attached Thumbnails R10 brake master cylinder upgrade-imageuploadedbyaussiefrogs1394703028.760493.jpg  
    Last edited by J-man; 14th March 2014 at 09:53 AM.
    cheers,

    John

  9. #9
    Fellow Frogger! rubyalpine's Avatar
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    Thanks for that John.

    Henry

  10. #10
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    Default Dual system ?

    Hi
    My manual says that the R10 in the USA had a dual master cylinder and split system. Is that true and are the master cylinders available ? A drop in part probably
    jaahn

  11. #11
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    Quote Originally Posted by jaahn View Post
    Hi
    My manual says that the R10 in the USA had a dual master cylinder and split system. Is that true and are the master cylinders available ? A drop in part probably
    jaahn
    Gee, that is interesting. Exactly which manual do you have please?
    JohnW

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    The Manic GT cars I have all ran the dual master cylinder 19mm and a safety proportioning valve. The Manic years were 1970 & 1971 R8 or R10 platforms .
    I also heard of people adapting the Volkswagen BUG master, cylinders for use on the R8&10 cars. Volkswagen bugs used a 19mm dual master with 4 lines 2 front & 2 back . They also were readily available here in Canada.

    My Hanes books has reference to the dual master set up with the proportioning valves.

    Manic GT

  13. #13
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    Quote Originally Posted by manicgt View Post
    The Manic GT cars I have all ran the dual master cylinder 19mm and a safety proportioning valve. The Manic years were 1970 & 1971 R8 or R10 platforms .
    I also heard of people adapting the Volkswagen BUG master, cylinders for use on the R8&10 cars. Volkswagen bugs used a 19mm dual master with 4 lines 2 front & 2 back . They also were readily available here in Canada.

    My Hanes books has reference to the dual master set up with the proportioning valves.

    Manic GT
    There you go! I must have one or more manuals that are too early. My R10 (R1190) factory parts manual doesn't show them.

    Thanks for the information.
    JohnW

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  14. #14
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    Quote Originally Posted by jaahn View Post
    Hi
    My manual says that the R10 in the USA had a dual master cylinder and split system. Is that true and are the master cylinders available ?
    That's correct. They were fitted from 1968 model onwards, and also fitted to the Canadian spec, and some South American and certain Euro market vehicles as well. Similar, if not the same, cylinder as fitted to the Alpine A110, so the part should be available through the usual Renault/Alpine suppliers. Note that for the R8/10 fitting though there was a different pedal and pushrod fitted as well, also that the cylinder was only fitted to LHD market vehicles as well.

    I fuzzily recall from distant past that the A110 cylinder is not a "bolt-in" modification for the R8/10, in that there are clearance issues between the cylinder and crossmember for the RHD vehicles. No doubt though, others will have done a dual circuit modification for the R8/10 that suits a RHD application.

    I've obviously got a death-wish, having an unmodified single-circuit system with 4.5" pizza cutter rims shod with XZX tyres. My head would hurt if I had to think about the logistics to cover all the issues in modifying it to reasonably modern specs, and I admire those who can do so.

    The factory dual circuit details are outlined in parts catalogue R8 1968-1971 PR 700 (3rd part) Derniere Edition issued 12/1972 on page 58.45.1. R10 parts catalogue 1965-1971 PR 832 Derniere Edition issued 12/1972 on page 58.33.1 and detailed in Workshop Manual MR 131 1st edition R1190 R1192 (R10) Amendment No 4 issued July 1970.
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  15. #15
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    The dual circuit master cylinder would have to have a different size bore would it not as it is only actuating two callipers? Or did they just go with a different pedal feel, or is the pedal ratio different.

    From my understanding of it all just putting a VH44 on a setup that was not designed to be boosted will give an undesirable pedal feel due to the pedal ratio and the master cylinder bore. Once I have my pedal bar out I'll measure the pedal ratio before jumping in any direction. As others have stated unmodified brakes work ok but is this compared to modern brakes boosted or not.

    The best calliper I've found is still the rear two 38mm pot calliper of the back of a R33 skyline. Problem here is the lack of handbrake but they would be great on the front. If you were to go a separate spot calliper for the hand brake I think they could be used on all four corners and just bias them appropriately.

    What I'll probably end up doing is leaving it stock with the the VH44 to get is passed then look at changing it down the path. I have owed a single circuit non boosted car that was my daily driver before, four wheel drum brakes, great until you want to stop.

  16. #16
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    Thanks Simon. I knew you'd come through about now!
    JohnW

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    Quote Originally Posted by JohnW View Post
    Gee, that is interesting. Exactly which manual do you have please?
    Hi John
    My manual is an Intereurope No 143, Renault R10, R1190, R1192 from 1966.
    Cheers Jaahn
    Last edited by jaahn; 17th March 2014 at 11:48 AM. Reason: did I write 1996 ??? :)

  18. #18
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    Quote Originally Posted by Simon View Post
    ... Similar, if not the same, cylinder as fitted to the Alpine A110, so the part should be available through the usual Renault/Alpine suppliers. Note that for the R8/10 fitting though there was a different pedal and pushrod fitted as well, also that the cylinder was only fitted to LHD market vehicles as well.

    I fuzzily recall from distant past that the A110 cylinder is not a "bolt-in" modification for the R8/10, in that there are clearance issues between the cylinder and crossmember for the RHD vehicles. No doubt though, others will have done a dual circuit modification for the R8/10 that suits a RHD application.
    ....
    They are identical for the 19mm versions.
    The A110's 22mm version was only used in combination with the groupe IV brake system (front 48mm caliper from R16 and rear 45mm caliper from Matra Bagheera or Fiat 130).
    Both are available at Mecaparts, but rather expensive ~310Ä excl. VAT

    http://www.mecaparts.com/PhotosPieces/mp3302.jpg

  19. #19
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    Quote Originally Posted by jaahn View Post
    Hi John
    My manual is an Intereurope No 143, Renault R10, R1190, R1192 from 1996.
    Cheers Jaahn
    I should have looked more closely. My 1973 Haynes manual has a full page or so with drawings.
    JohnW

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  20. #20
    1000+ Posts alan moore's Avatar
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    I fitted a dual master cylinder to my R10 braked 4CV. It is a 22mm ATE brand one for an 80's BMW (might be 520) of some type that I picked up from the wreckers. I prefer the heavier pedal with less travel. I have no booster. I fitted new brake lines with an inline brake light pressure switch, rather than the one on the end of the master cylinder like an R10 or A110. It bolted straight in place only that I drilled the mount out to fit 8mm bolts instead of the standard 6mm on the 4CV.

    I did originally look to buy a tandem A110 one, but was turned off by the price.
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  21. #21
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    I also has a look in the Haynes manual last night, tandem master cylinder.

    Having a general look around I came across some nice calipers, if you have some money to burn
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  22. #22
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    g'day, smee again, 4 years after the conversation ended - again !
    resto on my 10 is coming along nicely now and as one would expect, the brakes are "not good" from lack of use
    I'm expecting a little more spirited performance from the Weber and the rebuilt 10S head, so I'm considering brake issues - I don't want to get too involved so I am looking at simply removing the proportioning valve and replacing the 22mm master cylinder with a 19mm one
    can anyone tell me if they have a 19mm unit they would like to sell/swap pls
    cheers
    BP

  23. #23
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    A while back I pulled apart around 25 R8/10 brake callipers and found that all but a couple had been assembled incorrectly - and it may have been sheer chance those were done correctly.

    The critical part, ensuring the gap in the circlip aligned with the bleed nipple, was the most overlooked flaw.Thus more or less ensuring air was trapped in the caliper.

    The cars on which these brakes were installed would almost certainly had appallingly spongey brakes.
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  24. #24
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    Quote Originally Posted by Exfrogger View Post
    A while back I pulled apart around 25 R8/10 brake callipers and found that all but a couple had been assembled incorrectly - and it may have been sheer chance those were done correctly.

    The critical part, ensuring the gap in the circlip aligned with the bleed nipple, was the most overlooked flaw.Thus more or less ensuring air was trapped in the caliper.

    The cars on which these brakes were installed would almost certainly had appallingly spongey brakes.
    Quite agree. Despite being careful, I found to my embarrassment that I'd made that exact mistake last year when sorting out brakes that just weren't quite right on the R8. However, that fixed, they still weren't right. The two things that really improved matters were (a) throwing away all the brake hoses even though they "looked OK" and replacing them with stainless braided units and (b) paying particular attention to the master cylinder piston clearance specification. For the first time in many years, the brakes gave confidence instead of just being not quite right. So, it is all attention to detail..... I've stuck with the 22 mm MC in the interests of reduced pedal travel - with nice clean callipers and silicone fluid, they are quite light enough for me.

    Cheers
    JohnW

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