Rear brakes locking up information for you

[xm20k]

Forgot about the residual pressure valve for the rear drums as I'm disk/disk so wasn't needed in my application.

 

[Sgt Gus]

So, basically (if I understand) the new aftermarket combination valve doesn't proportion (70/30) correctly? Thus we install a little proportioning (inline to rear) to adjust pressure down because rears sometimes lock up? Our combination valve is too generic, they are very specific in their metering and unavailable? Thus wil wood comes in, we'll fix your old s$!t because farming out to China doesn't work. Oops rant? Slap me as you may.

 

[xm20k]

I kept hearing that and that a lot of them were junk and failing or sticking and causing one end or the other from having brakes or being locked up and not releasing.

Since I was replacing the entire system any ways adding the Wilwood valve on to the order was not a big deal what's 100 bucks when you've got almost 4K in the rest of the system.

My truck sat for years at a time in a storage building was registered 4 times for 4 years each time. The last time before I bought it, it sat for 12 years almost the entire brake system was full of solidified gunk. I started to pick my way thru it and at some point decided screw it, I want it on the road, so it all goes.

 

[Ricko1966]

So, basically (if I understand) the new aftermarket combination valve doesn't proportion (70/30) correctly? Thus we install a little proportioning (inline to rear) to adjust pressure down because rears sometimes lock up? Our combination valve is too generic, they are very specific in their metering and unavailable? Thus wil wood comes in, we'll fix your old s$!t because farming out to China doesn't work. Oops rant? Slap me as you may.

No. The adjustable proportioning valves pictured,only do preportioning and distribution,they do not have a standoff valve or a shuttle valve in them. The non adjustable combination valves that do proportioning,standoff,and have the shuttle valve are very generic. GM used many different combination valves depending on what brakes you had. The aftermarket is one size fits all. So when you start mixing and matching your front brakes,rear brakes,size of brakes,type of brakes. According to Willwood is use their adjustable proportioning distribution block,but you won't a have a stand off valve,so they say the answer for that is put a 10lb residual pressure valve in the rear brake line on drum brake cars.

 

[xm20k]

They have different valves for different applications most will use the 10lbs valve but they make others like 2lbs 5lbs etc.

Example a manual disk drum setup on a T bucket due to its lite weight might use a 2 lbs valve

 

[Sgt Gus]

So, breakbooster/master cylinder, then Wilwood adjustable proporportioning block, then same combination valve (has standoff and shuttle), then 10lb residual pressure valve in-line somewhere in-line for rear?

Do I potentially need to change the type of combination valve (PV2 generic, although I specified year, front disc and size 13" of drums)