So I was driving and the brake peddle started going to the floor when I slowed. It pumped up a bit after I drive some then went weak. I turned around and when I got home hooked up the MT 2500. No codes. I added some fluid but it still went down. When I tried to check the ABS it said it could not communicate. It was asking for me to hook up another wire??? I have the serial port connected to the OBD plug and the power source is the cig lighter. It seems like it was asking me to use a different power source but I don't have one???? I got 2 other cartridges a bunch of keys I have no idea what to do with yet, and some dongles to connect to different rigs.

Any ideas what mi9ght be the problem with the MT2500? AFAIK I am totally up to date with all SnapOn issued updates. http://buy1.snapon.com/products/diagnostics/cartridge_chooser.asp
EDIT I just noticed I don't have this cartridge. MT25002799 ABS Troubleshooter IDK if that matters.

I used the other rig and when I got back I noticed an oil spot near the back driver side wheel. It was brake fluid. I am too tired to crawl under it right now but I suspect I busted a hose or something sprung a leak.

 

My truck did this when I had a defective master, both lights come on when the switch detects a pressure difference. Either a leak or faulty master.

 

Don't know how similar your truck is to my 90, but there are two units...a rear ABS unit and a front proportioning valve/metering valve, both on the frame rail of the driver's side. The proportioning unit has a switch on the top that drives the brake light, and it detects pressure differential as the previous poster mentioned. I just took mine apart and it was pretty gunked up, and the internal plunger that shifts back/forth was stuck. Or you might actually have a pressure differential due to a leak somewhere.

 

Thanks Thomas, Robert, I'm hoping its a leaking hose. It is 22 years old. I'm happy I installed the new rotars, calipers, and bearings on the front. IDK when I'll get to it.

 

Onemore94dak - I'd HIGHLY consider replacing ALL the flex hoses (both front; one at the rear axle) due to age.

RwP

 

Thanks Ralph, Good Idea. I may get to it next week.

 

If you order them don't forget the copper crush washers...you'll need to replace them and the hoses I ordered didn't come with them. Just one more of those missing parts I've run into in my build.

 

Does anyone know about this kit and this company? http://ssbrakes.com/i-10092241-disc-...tors-a157.html The instructions seem to require that I know a lot of stuff I don;t know but it does come with new brake lines I'm leary of opening the differential I've never done that.

 

Can't attest to that kit....seems a bit pricey....I redid drums in back and discs in front including new drums and new rotors for cheaper than that using rock auto.

As to the differential if you just need to pull the axles it's a piece of cake IF you can get the locking pin out without issue. Mine was stripped and I had to weld a wrench on it to get it out. If you go further than that and take out the pumpkin you need a special tool to reset the gears and preloads. I have the tool and it's not too bad a process...lots of measuring with a dial micrometer.

 

I had some time to look at the FSM a bit and the MT 2500 plugs into the light blue plug under the steering wheel and there is also one on the passenger side just above the kick plate to test the ABS and RWAL respectively. I have RWAl and do not have the correct plug for either. I still need to read the diagnostic sections but now I know I need a new part for the MT2500 to be able to read the RWAL codes. I haven't found anything about both lights being lit yet.
As for the MT2500 keys, I think I mentioned I did not know what to do with them. I noticed I do have an OBDII plug and dongle for my MT2500 and the keys plug into that.
Ordered plug the MT 2500-31 CHRY-2 should have it by the 20th.