Disc brake proportioning valve/ brake failure warning switch

[Blue Viking]

I am installing the Forte Hydroboost setup with the Wilwood disc brakes. I would like to incorporate a brake line failure switch and also set the bias on the brakes. All the adjustable brake proportioning valves I've found only have a brake light switch. The common brass proportioning valves/ distribution blocks have the brake failure warning switch, but they are fixed with regards to reducing the pressure to the rear. Any suggestions? Does anyone know of an adjustable proportioning valve with a brake failure switch?

[CraigS]

Only one I am familiar w/ is the old Mustang unit. Back in the day we used to gut the proportioning function.
Here are several versions.
https://www.cjponyparts.com/mustang-...ks/c/60030150/
This the plug.
https://lmr.com/item/M2450A/Mustang-...ing-Valve-Plug
Here is the diagram from Ford.
BrakeControlValvecopy by craig stuard, on Flickr
My caution is this. It is extremely rare, nearly unheard of, for an FFR to need less rear brake. That is why we gutted the block to get rid of the proportioning function which reduced rear brake.

[rich grsc]

I am installing the Forte Hydroboost setup with the Wilwood disc brakes. I would like to incorporate a brake line failure switch and also set the bias on the brakes. All the adjustable brake proportioning valves I've found only have a brake light switch. The common brass proportioning valves/ distribution blocks have the brake failure warning switch, but they are fixed with regards to reducing the pressure to the rear. Any suggestions? Does anyone know of an adjustable proportioning valve with a brake failure switch?

Cant help with what valve to use, I don't think you should ever use a valve to reduce braking. As for your setup, it has been repeatedly advised not to use a powered booster with the Wilwood calipers.

[Blue Viking]

Only one I am familiar w/ is the old Mustang unit. Back in the day we used to gut the proportioning function.
Here are several versions.
https://www.cjponyparts.com/mustang-...ks/c/60030150/
This the plug.
https://lmr.com/item/M2450A/Mustang-...ing-Valve-Plug
Here is the diagram from Ford.
BrakeControlValvecopy by craig stuard, on Flickr
My caution is this. It is extremely rare, nearly unheard of, for an FFR to need less rear brake. That is why we gutted the block to get rid of the proportioning function which reduced rear brake.

Thank you very much for the answer, very helpful. Actually i'm thinking the 6 piston calipers in front vs 4 piston in the rear will provide the necessary bias. My main objective here is to achieve a warning in case of brake fluid leakage. Not that i absolutely have to have it, but i think it is a requirement for approval. Removing the proportioning valve part is a great idea. That would allow me to use it as a distribution block and brake warning switch only.

[Blue Viking]

Cant help with what valve to use, I don't think you should ever use a valve to reduce braking. As for your setup, it has been repeatedly advised not to use a powered booster with the Wilwood calipers.

Yes i'm well aware of that. I know the hydroboost is kinda on/off Will give it a try anyway. Thinking that controlling the hydraulic pressure to the unit will allow me some degree of tunability.

[Peer]

My main objective here is to achieve a warning in case of brake fluid leakage. Not that i absolutely have to have it, but i think it is a requirement for approval.

I have been dealing with the same issue as well, as I guess Your from Norway, as I am (Tønsberg)
It's mandatory in Norway to have some sort of warning light when the brake fluid level is getting low. The answer I got, was to use a pressure differential valve with warning light switch OR a brake fluid reservoir with "low level" sender to light up a warning light inside car.
I bought a valve from MG, Rover etc., but decided not to use it. Send me a PM if Your interested in that. Its basicaly a block with 2 inputs and 2 outputs (front and rear), with a pressure switch between the 2 ports.

Send me also some info of Your car etc. on PM, so we can keep in contact


Per Mathisen

[Blue Viking]

I have been dealing with the same issue as well, as I guess Your from Norway, as I am (Tønsberg)
It's mandatory in Norway to have some sort of warning light when the brake fluid level is getting low. The answer I got, was to use a pressure differential valve with warning light switch OR a brake fluid reservoir with "low level" sender to light up a warning light inside car.
I bought a valve from MG, Rover etc., but decided not to use it. Send me a PM if Your interested in that. Its basicaly a block with 2 inputs and 2 outputs (front and rear), with a pressure switch between the 2 ports.

Send me also some info of Your car etc. on PM, so we can keep in contact


Per Mathisen

Will do!

[Papa]

Just reading through this thread and I have to say the simplest approach sounds like the reservoir with the low level indicator. As an engineer, I've learned to use the KISS principle whenever possible.

[Blue Viking]

Just reading through this thread and I have to say the simplest approach sounds like the reservoir with the low level indicator. As an engineer, I've learned to use the KISS principle whenever possible.

I guess the last S applies to me, I'm not very good at keeping things simple......

[edwardb]

Can't help with the questions (proportioning valve, warning switch) but FWIW my #7750 build had hydroboost assist with Wilwood brakes. I too heard the comments about it would be "on/off" sensitivity. It wasn't. Worked very well with exactly the feel you would expect from power assisted brakes. Not touchy at all.

[Olli]

Since you are already buying parts from Forte ask him about the level switch that he sells. https://fortesparts.com/product/cnc-...-fluid-sensor/

Olli

[Avalanche325]

I would go for level sensors in the reservoirs. They will do what you are looking for.

Brake failure switches usually work off of differential pressure between the front and rear systems. The light would only come on when you are hitting the brakes. You will already be well aware that there is a brake problem and need new underwear by the time the light comes on.

Non adjustable brake bias blocks are usually very system / car specific. I would not put one into a system that it is not designed for and hope for the best, then have to start playing with pad combinations, etc. to get it right. The way to adjust bias for the Wilwoods is by doing it manually at the balance bar. There is a remote adjuster that you can mount in the car and adjust to your hearts content. You will find that once you are set up, you will rarely touch it. It is nice for set up though. The other option would be an adjustable Heidts valve.

There is more to bias that how many pistons. But, you can trust that the system is engineered correctly. Until you start adding in components that weren't in the design, that is.

[Blue Viking]

Can't help with the questions (proportioning valve, warning switch) but FWIW my #7750 build had hydroboost assist with Wilwood brakes. I too heard the comments about it would be "on/off" sensitivity. It wasn't. Worked very well with exactly the feel you would expect from power assisted brakes. Not touchy at all.

Thank you very much for that info, most helpful. I have the 2,5 turn lock to lock steering as well, so i figured I'd buy an adjustable power steering pump, assuming i can tailor the feel to my taste. Time will show. Did you do anything with the bias, or was it fine as is?

[Blue Viking]

I would go for level sensors in the reservoirs. They will do what you are looking for.

Brake failure switches usually work off of differential pressure between the front and rear systems. The light would only come on when you are hitting the brakes. You will already be well aware that there is a brake problem and need new underwear by the time the light comes on.

Non adjustable brake bias blocks are usually very system / car specific. I would not put one into a system that it is not designed for and hope for the best, then have to start playing with pad combinations, etc. to get it right. The way to adjust bias for the Wilwoods is by doing it manually at the balance bar. There is a remote adjuster that you can mount in the car and adjust to your hearts content. You will find that once you are set up, you will rarely touch it. It is nice for set up though. The other option would be an adjustable Heidts valve.

There is more to bias that how many pistons. But, you can trust that the system is engineered correctly. Until you start adding in components that weren't in the design, that is.

Lots of good points# I am aware that the non adjustable blocks are car / system specific, that's why I was looking for an alternative. I will check how the brakes work before doing anything with the bias, chances are i won't have to do anything.

[Blue Viking]

Since you are already buying parts from Forte ask him about the level switch that he sells. https://fortesparts.com/product/cnc-...-fluid-sensor/

Olli

I think that's for the CNC reservoirs. I have Tilton reservoirs, haven't seen level sensors for those yet.

[tonywy]

So, to read this correctly you want to increase rear brake pressure on a FFR car correct ? I am in the middle of fitting Wilwoods new " compact mustang brake master w/ an adjustable rear proportional valve "which will allow me to increase or decrease rear brake pressure.

[CraigS]

So, to read this correctly you want to increase rear brake pressure on a FFR car correct ? Generally yes especially when using Fox Mustang parts since they were designed for the front heavy Mustang. While I haven't tried any of the Wilwood setups, I suspect they are designed for a F to R balance that is correct for an FFR.

I am in the middle of fitting Wilwoods new " compact mustang brake master w/ an adjustable rear proportional valve "which will allow me to increase or decrease rear brake pressure.

I just looked through the Wilwood info on the valve. As best as I can tell it is a typical brake pressure valve which can only reduce pressure to the circuit it is mounted in. If it happened that all the other components of your system produced balance when the valve is somewhere in the middle of it's range it could increase or decrease rear brake pressure from that balance point. But technically all it can do is reduce pressure.

[edwardb]

Thank you very much for that info, most helpful. I have the 2,5 turn lock to lock steering as well, so i figured I'd buy an adjustable power steering pump, assuming i can tailor the feel to my taste. Time will show. Did you do anything with the bias, or was it fine as is?

No, my setup didn't have a proportioning valve and never felt the need to have one. Front/back bias was fine. Mild disclaimer, I'm 99.9% street driving and nothing very extreme.

[Blue Viking]

No, my setup didn't have a proportioning valve and never felt the need to have one. Front/back bias was fine. Mild disclaimer, I'm 99.9% street driving and nothing very extreme.

Perfect! That is exactly what i thought but needed to find out for sure! I'll just set up a simple distribution block with the shuttle valve for the warning then, and be done with it.

[Avalanche325]

I really think the shuttle valve is next to useless. Maybe if you lost the rears you wouldn't notice with casual driving. But if you lose the fronts, you ain't gonna need a light to tell you.

I was driving a friends 64 Imperial and the brakes failed. The light came on, but the pedal had already hit the floor, so it wasn't telling me anything I didn't already know. I was literally headed for a Police car that had the road blocked off for an accident. Luckily, there was a dirt road just before the police car that I squealed wheels onto.

Here is a Wilwood cap with sensor. Maybe you could see if the threads are the same as the Tiltons.
https://dragillustrated.com/wilwood-...level-sensors/

Edit : Never mind - On Pegasus racing it specifically says "does not fit Tilton."

[Blue Viking]

I have been dealing with the same issue as well, as I guess Your from Norway, as I am (Tønsberg)
It's mandatory in Norway to have some sort of warning light when the brake fluid level is getting low. The answer I got, was to use a pressure differential valve with warning light switch OR a brake fluid reservoir with "low level" sender to light up a warning light inside car.
I bought a valve from MG, Rover etc., but decided not to use it. Send me a PM if Your interested in that. Its basicaly a block with 2 inputs and 2 outputs (front and rear), with a pressure switch between the 2 ports.

Send me also some info of Your car etc. on PM, so we can keep in contact


Per Mathisen

Did you get my PM?

[Blue Viking]

I really think the shuttle valve is next to useless. Maybe if you lost the rears you wouldn't notice with casual driving. But if you lose the fronts, you ain't gonna need a light to tell you.

I was driving a friends 64 Imperial and the brakes failed. The light came on, but the pedal had already hit the floor, so it wasn't telling me anything I didn't already know. I was literally headed for a Police car that had the road blocked off for an accident. Luckily, there was a dirt road just before the police car that I squealed wheels onto.

Here is a Wilwood cap with sensor. Maybe you could see if the threads are the same as the Tiltons.
https://dragillustrated.com/wilwood-...level-sensors/

Edit : Never mind - On Pegasus racing it specifically says "does not fit Tilton."

The authorities require a warning-light for the brakes, so i'm kinda obliged to install it if i want plates on the car.