Anyone ever had a problem with a brake differential pressure switch?
also known as the "proportioning valve"? It's right next to the master cylinder on a non PB '67. The brake light stays lit on the dash but I've narrowed it down to this switch. Do they go bad? I've heard you can take it out and soak it in denatured alcohol to clean up the insides. Thanks for any thoughts on this. PT
-
-
Re: Anyone ever had a problem with a brake differential pressure switch?
also known as the "proportioning valve"? It's right next to the master cylinder on a non PB '67. The brake light stays lit on the dash but I've narrowed it down to this switch. Do they go bad? I've heard you can take it out and soak it in denatured alcohol to clean up the insides. Thanks for any thoughts on this. PT
Patrick-----
Yes, they do "go bad". In general, what occurs is that the piston sticks off-center and causes the brake warning light to stay illuminated. You may be able to clean it and free it up using the method you described.In Appreciation of John Hinckley -
Re: Anyone ever had a problem with a brake differential pressure switch?
Pat ,
inside the block is a brass plunger. It will move to what ever side is not producing pressuer. It is desiged as a fail safe so you don't lose both front and back brakes at the same time.
I would remove the terminal on the bottom, watch as there are orings and nylon sets/ insulators. Once removed you can look and see if the plunger has moved and is making contact with the terminal when installed. If it is you should be able to take a vety thin punch and move the plunger through the brass seats ont the 2 outer ends. If the punch wont fit the brass seat can be removed to accomplish this..
RichComment
-
Re: Anyone ever had a problem with a brake differential pressure switch?
Thanks for the information guys. Rich, thanks for the heads up on the exploding spring, I hate when that happens. Usually the spring shoots out of whatever I'm taking apart and ends up on the floor 10 feet away and I can't find it.
PT
Comment
-
Re: Anyone ever had a problem with a brake differential pressure switch?
UUUHH Pat there is a slight chance that a spring may come flying out. OOppss it's been awhile since I took one apart. I'm just glad it didnt get your eye.
RichComment
-
Re: Anyone ever had a problem with a brake differential pressure switch?
Also while you have the plunger out check the 2 orings as that might be the cause of the failure.
RichComment
-
Re: Anyone ever had a problem with a brake differential pressure switch?
Pat:
I had mine rebuilt about 10 years ago by DR VETTE (now Corvette Stainless Steel Brakes)....so there are/were folks who can rebuild. I have not seen a "do-it-yourself" rebuild kit available. There may be a problem getting the correct rebuild parts and o-rings.
These blocks are also now available in reproduction. Not certain who the manufacturer is, but check LICS or Paragon (or others) catalog.
Larry
LATE EDIT: New or rebuilt blocks are available from Lone Star Caliper in Texas. They should be able to rebuild yours if you contact them.Comment
-
Re: Anyone ever had a problem with a brake differential pressure switch?
Thanks Larry, for now I think I will just soak it in denatured alcohol to see if that works. If not, I will try to get it rebuilt since it's the original. I've looked at the repops at LICS and Paragon but they're made in China. They are probably at best, functional replacements that a Judge would pick up in a heartbeat. They will not show you a close up picture of what they really look like. PTComment
Comment