Rear brake compensator/bias valve

[jxke]

Hi, I’m usually pretty good at finding parts I need but I’m really stumped on a rear brake pressure regulating valve for my 1986 Renault 5 - this type was only on the very early Super 5’s as it got superseded.

Does anyone know where I could get one or have one stashed away? Or know if it’s shared with any other Renault model?

part number is 7700729131

 

[mr-reno-139]

Easiest thing is to bypass it it is only a pressure limiting valve later cars had the valves built into each wheel cylinder at this point the brake shoe back plate was also changed to a different design

 

[mr-reno-139]

To change to the different shoes and cylinders would involve using the later back plate complete burgers

 

[Andymag]

Hi, I’m usually pretty good at finding parts I need but I’m really stumped on a rear brake pressure regulating valve for my 1986 Renault 5 - this type was only on the very early Super 5’s as it got superseded.

Does anyone know where I could get one or have one stashed away? Or know if it’s shared with any other Renault model?

part number is 7700729131

View attachment 25963View attachment 25964

Hi, I’m in the same situation. Can’t find the part anywhere. Did you eventually find a solution?
Cheers!

 

[mr-reno-139]

if money is no object
personally i would fit m10 brake pipe joiner and not worry about it https://www.all4renault.com/products/a7700729131-bomba-repartidora-4-ligacoes/

 

[seb67]

Bonjour tout le monde. Je suis tombé sur votre forum et j'ai vu que c'était compliqué d'en trouver un. J'en vends un neuf et d'origine a petit prix pour se que ça intéresse. https://images.app.goo.gl/iMQHZqaqC1GCU3DJA

 

[seb67]

Bonjour, je suis généralement assez doué pour trouver les pièces dont j'ai besoin, mais je suis vraiment perplexe quant à une soupape de régulation de pression de frein arrière pour ma Renault 5 de 1986 - ce type n'était présent que sur les tout premiers Super 5 car il a été remplacé.

Est-ce que quelqu'un sait où je pourrais m'en procurer un ou en avoir un de côté ? Ou sait-il s'il est partagé avec un autre modèle Renault ?

le numéro de pièce est 7700729131

View attachment 25963View attachment 25964

Bonjour à tous le monde. Je suis tombé sur votre forum et j'ai vu que c'était compliqué d'en trouver un. J'en vends un neuf et d'origine à petit prix pour se que ça intéresse. https://images.app.goo.gl/iMQHZqaqC1GCU3DJA

 

[Pascal's pilot]

I worry about you guys sometimes.

Why did a car maker go to the expense of fitting a rear brake limiter valve ? (Believe that me they do not spend 1 penny more than they have to on any car.)

Because the front brakes must always lock first for safety reasons.

Pre ABS, with locked front wheels the car will slide in a straight line as long as the rear wheels are still rotating or lock later.
Before rear valves brake manufactures made the front drum or disc brake higher efficiency than the rear by selecting the size of cylinder and Mu level of the pad or lining.
NB. Mu level is just an efficiency rating if you like, typical disc pad material is around 0.4Mu.

Conversely, the rears where controlled by careful selection of wheel cylinder size and again Mu level of the pad/ling.

If the rears lock first, then there is a strong chance the rear end will come round suddenly and put the car in a spin.
Wet road surfaces high light the problem.

Deleting or bypassing the limiting valve is dangerous and a no, no.

So if you cannot find the correct valve fitted to your R5 my humble suggestion would be look for a similar size/weight/drive configuration car to rob some from.
IE. front engine and FWD, try a Ford ka (Mk1 original type).
Ka's are fitted with 2 inline Pressure Conscious Reducing Valves (one under each rear wing)
The cut off pressure of the valve may not be exactly the same as a R5 but it won't be far off and you will be safe.
There is an arrow marked on the body to indicate direction of fluid flow.

If there is a Renault equivalent fit that; but please don't feed full pressure to the rear brakes or one wet night you will be .......................

Regards Dave (Ex vehicle brake test engineer) retired.

 

[mr-reno-139]

Just my thoughts post 1987 all rear drum brake super 5 9 11 Clio have the valves built into wheel cylinders
Identified by M12 input threads
Both bendix and girling versions are available
Not sure bolt spacing on back plate compatible

 

[Pascal's pilot]

Hi Paul,

If these wheel cylinders fit jxke's car, they are the best solution.

 

[Pascal's pilot]

Most important is that the wheel cylinders must be the same size/diameter.