maybe368

That is the low vacuum switch for the brake or abs light ( can't remember which). Check rock auto, I think they are available...Mark

wannadiesel

Low vacuum sensor. Looks like you just broke the nipple off. Here's an old thread with a low-buck repair "tip."
https://www.dieseltruckresource.com/...ighlight=tweco

92betsy

Thanks for the link, I will fix that next chance I get. Still can't get the brakes to work. I had a moment of free time to crawl under yesterday no buldges in any lines. Still need to check the combination valve hopefully Friday I can get a moment. Getting real sick of not driving my truck. The wifes little 4-banger doesn't have the power I am so used to having with the truck.

jogl

Have you blocked off the rears yet to see if you have a front or rear problem? I'll bet dollars to donuts that your problem is in the rear. And I'll put another donut on the line and say the problem is the abs crap box.

JP.

92betsy

No I haven't blocked off the lines yet no time with work and school I've been busy and it rained my last day off all day. The ABS valve has been removed already when first trying to figure this out.

92betsy

Ok still no progress tried some more parts blocked everything off one by one and no dice. Next I'm gonna try to do my rear brake shoes for comfort sake and redo a few lines in the system just to reassure myself. Still can get the peddle to get very firm while bleeding but as soon as I put it in gear it softens up and hits the firewall. Same problem I have had since the start.

maxwellp

If you blocked off the front and rear brakes and still have a soft peddle, the second master cylinder is also not good. In 25 plus years of working on cars and trucks I have never replaced a proportioning valve.

92betsy

I am now on the 4th master cylinder, 2nd booster, and while doing this I have also replaced the front calipers and shoes. I know it has been a while since the backs have been done so I'll do them for comfort sake. But the lines are also 19 years old so Ill just get a roll of line and redo them. At this point I figure I will rebuild as much of them as possible while the truck is down just to make myself feel better knowing it has all been redone. I have been wondering if I should just give the master cylinder back to autozone and get a NAPA one instead of keep using autozone ones since I haven't had any success with them.

92betsy

So after 6 master cylinders 3 boosters and still no pressure building in the system I about gave up. Couldn't afford a shop with several layoffs in the last few months and severe lack of funds. So I read on another site that people had used newer set ups on their trucks with good result. So I installed a master cylinder and booster from a 96 1 ton and my brakes work perfect for the first time in several months. Great upgrade and easy modifications to install. So that was my problem the autozone rebuilt ones suck. My 96 one is brand new not rebuilt and solved all my issues. Thought I would just update this thread now that I got it fixed.

maybe368

A 96 Dodge right? And, was it a straight bolt on?...Mark

92betsy

Not a direct bolt on the two holes closest to the engine fit fine but I had to drill two new holes for the other studs. The hole in the rod to the peddle had to be enlarged a little bit also. And the studs are larger than the original ones so I had to go to autozone and got some "M10-1.50" nuts to fit it. Simple install and fixed my problem finally. It also sticks out a little farther and I had to remove my intake pipe on the innercooler to install the master cylinder but it went back on fine with no issues on clearance after the MC was bolted up.

maybe368

On my non-IC '90, the 2 studs are located just inside the bracket that is affixed to the fire wall. So they end up outside that bracket, right? There was no issue with the rod being centered? Thanks Mark

92betsy

Yes the 2 studs you drill for basically end up under the steering column versus inside the little bracket area they originally where in. There was no issues with anything in the way when drilling. And yes the rod fit fine after I drilled the hole just a little bigger it was centered properly for the peddle. Here is a link to the thread on CF that I got the idea from he has some pics so you can see what it looks like installed.

http://www.cumminsforum.com/forum/89...today-147.html

maybe368

Thanks, it is the last thing I am going to do to my $%^*&$@@$%**%^&*%$ brakes, even though they are working fine now. I said in an earlier brake thread that I cannot believe that EVERY rebuilt MC is bad, but I am beginning to believe it...Mark

Jim5870

Just curious, is the 96 a plastic resevoir type?