69 Brake Proportioning Valve

[Kelly H.]

The brake light in the dash remains on and I have determined the issue is with the proportioning valve. (pull off the brown wire and the light goes out) I have been spraying the connections to the valve for 3-4 months with AeroKroil and Blaster and still can't turn the nuts. Any tips on how to bust the nuts loose? I don't want to replace the brake lines but I'm tearing up the nuts with ViseGrips.

[Greg L.]

Re: 69 Brake Proportioning Valve

I good quality tube wrench usually works for me as long as the nuts aren't damaged too badly.

Are you sure it's the switch though and not air in one half of the brake system? I think air in the system is more likely than a bad switch.

[John H.]

Re: 69 Brake Proportioning Valve

It's not a proportioning valve - it's simply a distribution block that contains the differential pressure switch; it has no valving function at all.

Agree with Greg - a good line wrench (reinforced with Vise-Grips to keep it from spreading) should break them loose.

[Joe L.]

Re: 69 Brake Proportioning Valve

The brake light in the dash remains on and I have determined the issue is with the proportioning valve. (pull off the brown wire and the light goes out) I have been spraying the connections to the valve for 3-4 months with AeroKroil and Blaster and still can't turn the nuts. Any tips on how to bust the nuts loose? I don't want to replace the brake lines but I'm tearing up the nuts with ViseGrips.

Kelly------

The part that most concerns me is your last sentence. If you've damaged the wrenching surface of the tubing nuts too much, you're likely a "dead duck".

If you haven't, though, a tubing nut wrench as shown below and a 3/8" drive breaker bar will get the job done.

YOU ABSOLUTELY MUST SUPPORT THE BRASS SECTION OF THE BLOCK WITH A WRENCH WHILE YOU DO THIS. OTHERWISE, YOU'LL BREAK THE BLOCK FROM THE FRAME-ATTACHING BRACKET. Then, you'll for sure need a new block.

By the way, I agree with others that the most likely cause for the problem is not a failed block/switch, but air in the front or rear system.

[Joe L.]

Re: 69 Brake Proportioning Valve

Forgot to post the photo. Here it is:

[Dick W.]

Re: 69 Brake Proportioning Valve

Channel Lock makes a very good pair of stud pliers. I have had better results with them than I have with Vise Grips.

[Terry M.]

Re: 69 Brake Proportioning Valve

The brake light in the dash remains on and I have determined the issue is with the proportioning valve. (pull off the brown wire and the light goes out) I have been spraying the connections to the valve for 3-4 months with AeroKroil and Blaster and still can't turn the nuts. Any tips on how to bust the nuts loose? I don't want to replace the brake lines but I'm tearing up the nuts with ViseGrips.

Vice-grip brand makes a pair of locking pliers specifically for this kind of job. I have seen these pliers (without the fancy rubber grips) squeeze the B-nut enough to deform is slightly and break the rust bond to the tubing. It is very handy on fuel filters that have seen many winters int he salt encrusted Midwest.

http://www.irwin.com/irwin/consumer/jhtml/detail.jhtml?prodId=IrwinProd190006

Kelly, I think you will have two problems:
1) the damage you have already done
2) access with these Vice-Grip pliers.

[Kelly H.]

Re: 69 Brake Proportioning Valve

Thanks for the advice. I probably make things harder than need be. Makes sense to bleed the brake lines first.