Brake system refurbishment - cleaning proportioning valve

[TEXASYETI]

Am on the tail end of a full rehabilitation of my braking system on my 85 fj60. Have spent a lot of time reading previous threads but have not seen one issue covered:

Cleaning the proportioning valve.

Is this just a matter of spraying brake cleaner it is to get out any gunk and then just flush it really well during the bleeding process?

I have rebuilt the calipers, MC, new front pads, new rear shoes, new rear hardware kit, new rubber hoses, and a serious cleansing of the hardlines.

Almost there......

 

[hank14]

Are you sure the FJ60 has a proportioning valve?

 

[TEXASYETI]

I does. I've read just about all of the threads I could. It does not have the load-sensing thingie in the back but hanging right below the MC off the booster is the valve.

Anyone know if I need to do anything to clean it?

 

[haryv]

Out of hundreds of cars, never cleaned one but..

There is nothing wrong with cleaning a brake part if its old. I had a case point of my brakes on my own land cruiser just suddenly give out within 50 feet!!! imagine if I was on a hill? I lost all front brakes luckily, at a intersection. I took my master apart and it was full of rust and atmospheric gunk and won seal material. Brake fluid is hygroscopic meaning, it absorbs moisture from the air like a sponge that absorbs water. It comes in though the vent hole in the top of the reservoir cap.

I would take it apart, and learn from it. See if it has crap in it and check it for functionality.

 

[willflow]

Moisture can actually be drawn into the master through the casting too. All castings are porous steel or aluminum. They look like swiss cheese under a scope and they will pull in moisture. This is all why flushing your brakes is so important.

 

[SteveH]

If it's installed in the system, I would just run fresh brake fluid through it. If it's off the truck, then clean it with brake cleaner. You can re-bleed the proportioning valve later, if you want to introduce fresh fluid into it.