Anyone else doing brake proportioning valves? (Page 3/4)
pmbrunelle APR 19, 07:21 PM
The combination valve doesn't do anything with the front circuit other than split the line towards the left and right brakes.
Hydraulic pressure between both sides is (supposed to be) the same.

I would start by investigating the amount of weight on each tire.

If the front tires don't share the weight of the front end evenly, then the side supporting less weight will lock up prematurely.

This may be because you shifted weight around, or maybe you have cut springs that are not the same height/rate on both sides? If one spring is shorter, then there will be less weight on the tire having the shorter spring.

Do you have scales? I don't, so what I do is I drive to truck weigh stations off the freeway at night when nobody is there. Be sure to stay in the car while being weighed.

[This message has been edited by pmbrunelle (edited 04-19-2018).]

Patrick APR 19, 08:02 PM

quote
Originally posted by pmbrunelle:

what I do is I drive to truck weigh stations off the freeway at night when nobody is there.



I didn't know that was possible. Are the scales always "on"?
pmbrunelle APR 19, 09:22 PM

quote
Originally posted by Patrick:

I didn't know that was possible. Are the scales always "on"?



Here on the Québec autoroutes I travel on, yes, the scales are always left on. I can't say how it is in other jurisdictions though.
Not sure about the legality either, as there are "cars prohibited" signs at the entry point, but I figure that stopping momentarily at a closed weigh station isn't going to bother anyone.

There are flashing lights to indicate when trucks must stop for inspection; I avoid the station during these times, to not interfere with their operations.

The weighing platform is composed of multiple independent sections. It's arranged to measure the weight of each axle (or axle pair) on a big truck.

There are LED displays that are always on, and visible from the vantage point of the driver on the vehicle being weighed.
The display shows the weight per axle, and the total of all axles.

To figure the left/right distribution, you would have to drive with one side of car on pavement, and the other side on the scales, measuring half the car at a time.
Repeat for the other side.
La fiera APR 19, 10:13 PM


I didn't have a problem with brake bias but for faster stopping and to make the car rotate better at very short radius turns I installed one of these.
wftb APR 20, 08:05 AM

quote
Originally posted by La fiera:



I didn't have a problem with brake bias but for faster stopping and to make the car rotate better at very short radius turns I installed one of these.



So is your stock prop valve disabled? Is that additional valve on the front circuit or the rear circuit?
La fiera APR 20, 06:37 PM

quote
Originally posted by wftb:


So is your stock prop valve disabled? Is that additional valve on the front circuit or the rear circuit?



Yes, I disabled the rear circuit and use the adjustable prop. valve to adjust the pressure to the rear.
SP1200 APR 26, 06:04 PM

quote
Originally posted by La fiera:



I didn't have a problem with brake bias but for faster stopping and to make the car rotate better at very short radius turns I installed one of these.



Can I please have the details of this setup?
Is there a thread about it? write up? Part numbers ect?
wftb APR 26, 11:22 PM
The answer to my question did not make sense to me but i let it slide. You cannot disable the rear circuit of the prop valve. You disable the whole prop vave or you leave it alone.
La fiera APR 27, 02:52 PM
I've been looking for the information I used to do it but can't find it. If I remember correctly I modded the rear circuit so it can have full pressure and then installed the Jeg's proportioning unit in line. I'll keep looking.
wftb APR 27, 04:30 PM
Thanks