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Brake problems

Thanks for your support! :)

I released the handbrake to get some room for my hands when i fiddled with the master cylinder. So i'll put it back on before i continue now. I had no idea the hand brake did that. I have auto adjusting brakes though, hopefully they work.

I have bought 2 different diy bleeding kits - one where you connect a non reurn valve out on the wheel end (goes down into a can), and one where you put pressure on the top of the master cylinder containers. Unfortunately the lid on the pressure kit does not fit the R4, so i've drilled a small hole in one of the original lids and use a regular compressor (instead of a wheel). Both methods seems to work. I'll try the non return valve today, and if that does not work i'll phone my brother and do a 2 man bleed again.

Actually, i'm full of hope :) I'll let you know how it went!
 
Wohoo! Working brakes again, and better than ever :)

Summary: Changed hose l front, cylinder r rear, master cylinder, brake pads rear. Bled the system a few times according to Clementine's work order. Fixed the automatic brake adjusters, as Liam4R4SPARES suggested. Greased hand brake wire.

So that was an easy fix...not

Anyhoo, when i drove back into the garage the oil lamp lit up....pheeew..there's always something to do.

It's a big load of me chest to have working brakes again. Thank you for your suggestions, etc!
 
Good to hear they are working again.

Behind my technical advice is a cat whose brakes don't work at all. Braking takes a good push on the pedal for me, and when the brakes do lock up it's the back ones that go first. (And it's not the rear brake proportioning valve that's at fault - the front discs are completely shot).

I really must get around to replacing my front brake discs and pads. I drove a R4 with good front brakes recently and it was amazing. :D
 
As we are talking about brakes, do you (people with experience on both types of brakes) think that disc brakes on a R4 are far better than drum brakes? Or the improvement can be mainly seen when the brakes get wet? I assume that both types, especially drums, are in good shape. I have never driven a disc brake equipped R4, they are rare here, but have driven both drum and disc-braked 2CVs, and the difference is not that great, apart from shorter pedal travel.
 
My R4 came with drum brakes, after I first modified the engine, I could loose a pound of weight in sweat when braking. Then converted it to disk brakes and now it's only half a pound :wink:
It really makes a difference.
It's not only the braking capacity, but also the ability to get rid of the heat what matters.
 
Very true :) Mine has drum brakes, and they're good for short bursts of braking, after which they have to cool off for a while before they are actually useful again.

BTW - is it called brake pads on drum brakes?
 
We had a GTL with unboosted discs a few years ago and by those days standards the brakes were excellent, way better than drum equipped cars.
When I bought my current car ('68 model) the brakes were pretty ordinary. I had them overhauled, and at the same time asbestos brake linings became unavailable. The replacement Renault material seems a lot more spongey -uses more travel and more pressure for the same braking effort- and I know this was a general problem with other modern cars needing additional boost when this occurred. I put a remote booster on(similar to those on RHD Alfa Romeos and on 60's American cars). There are various brands, all very similar, available in two basic sizes. I also put a later model R4 dual circuit master cylinder on and put the booster to the front circuit only. I used the smaller size booster and in retrospect could have gone with the bigger one. Around town and even on the freeway, performance is fine if you are not using them the whole time. The biggest problem is having enough travel. Really they need a bigger bore master cylinder (which would require a bigger booster). Discs would be way better but you would definitely need a booster with them with modern pads.
 
Boosters!
Pieter, I've been thinking of fitting a booster, but what must I take into account to do that? What kind of booster should I choose? What are those remote boosters and how do they work?
 
Enrique, a remote booster has the master cylinder output as its input- that is, you connect the master cylinder front circuit line to the booster. The booster is then pushed by a piston like a wheel cylinder, instead of a pushrod. The rest is the same as a normal booster, with a vacuum cylinder supplying additional force, controlled by the applied force/pressure from the master cylinder. They are made in Australia by PBR but other companies used to make them- maybe not these days. They are great because you can put them anywhere, under the bonnet, or under a front mudguard.

The little one I used is the VH44. You can also use the big VH40 unit, or two VH 44's, one for the front and one for the rear circuit. Boosting the rear circuit is probably not worth it on an R4.

These are sold worldwide, try emailing PBR to find a local agent in your country. Here's their website: www.pbr.com.au

and the page on boosters

http://www.pbr.com.au/products/heavy/documents/PBRHydropowers.pdf

contact details for parts queries

PBR Aftermarket
264 East Boundary Rd
East Bentleigh
VIC 3165 Australia
Customer Service Centre
Phone : +61 1300 369 727
Facsimile : +61 1800 064 727
Email: pbr_enquiries@pbr.com.au


I hope this helps- I'll take a photo of my brake setup and post it.
 
Another solution would be the Lockheed brake booster that was fitted on English cars in the 60s. If you can find such a vehicle (Mini, Morris 1100, Land Rover to name the most common) at a scrapyard you can buy it fairly cheaply. Overhauling it should not cost too much.However, it has only one inlet (english master cylinders had one outlet and a 3-way union).So you will need a 3-to-1 union (or 2-to-1 if you would like to connect only the front brakes) as R4 master cylinders have 3 outlets.
 
Yes, a very similar unit. mid-late sixties Alfa Romeos also used a Lockheed or an italian (can't remember which brand) booster. I suspect they are all based on the Lockheed and started off being licence-built copies. On my car I blanked off one of the front outlets on the master cylinder and had a 2-way union on the booster outlet.
 
When you bleed your breaks you want to start with the brake thats the farthest away from the master cylinder in order to maintain good pressure.....on left hand drive cars the order would be:
rear passager side,
Rear driver side,
front passager side,
front driver side.

This allows you to pump all the air out of the system.

Also, after bleeding each break...recheck the fluid level in the master cylinder and top up as nessesary
 
Hey,
speaking of twin circuit master cylinders, can anyone tell me what bore diameters the F6 van and GTL twin circuit master cylinders have? Also what wheel cylinder bore a standard R1123 should have at the front and back?
Thanks
 
The tandem master cylinders are all 19mm diameter for both TL-GTL ang fourgon. Earlier fourgons had 22mm master cylinders.I have never repaired an F6 but I think they have 19mm master cylinders, too.
All drum braked R4s have 15/16"" (23.8mm) front wheel cylinders except the Spanish-built R2108 van (22mm). Rear wheel cylinders are always 3/4""-19mm on 1123 according to manuals.Fourgons used to have 7/8"-22mm rear wheel cylinders. I have found those cylinders on at least 1 R1123,but chances are that they were incorrectly fitted
 
Interesting- thanks Angel, I really appreciate it.

Does anyone else know what bore a tandem circuit F6 master cylinder should have? I must say I'm surprised the other ones are only 19mm. It seems awfully small given the wheel cylinder bore. It would seem to explain why getting sufficient pedal travel is so difficult on an R1123.
 
Many thanks everyone who posted here - I'm also planning a remote servo and a forum search has me just about there with a spec. I was worried about pedal travel too. I've used Lockheed servos on my MGs and they work well (and come with different bore diameters for different servo effect).

Anyone know the part number for the 22mm Fourgon master cylinder? It sounds like that would work well with 850 pedals and a reasonably strong servo.
 
7700511245. There is also the earlier part # 8546809 (all R4s before 1965 had 22mm master cylinders).
 
Yesterday I got a R4 for some repair work which is equipped with front disc brakes and Lockheed servo. Superb braking!!! Without losing too much of pedal feel, too. Unfortunately, cannot figure out which master cylinder diameter does it have. Very worthwhile modification.
 
That's encouraging. I've picked up a master cylinder from eBay. It's for an F4 I think so guessing maybe 22mm.

I reckon the disc brakes and self adjusting rears should do a lot to prevent brake travel problems over the manual adjust brakes.
 
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