i had new master cylinder put in on my truck today. and I seen abs light on so I told him about it. he said it should go out. drove it home 10 miles did ok. so I went out to truck abs light still on. I pop hood and seen plug unplug on master cylinder so I unlook battery plug it back in hook battery back up. now truck want move feels like breaks are locked. any help 5.0 auto trans
4x4

 

the ads light did go out when I plug in the plug to master cylinder

 

also I did unplug it didn't unlock wheels

 

called wrecker took to the shop no one there . anyway I starter truck before wrecker came. it loaded ok. came off flat bed he hard time getting off then he left I went to try start the truck wouldn't start turning over. so now wheels lock up and truck won't start

 

It sounds like the equalization port in the master cylinder might be blocked, and it's not letting the master depressurize. I'd put a new master cylinder on it and flush the fluid out through all four wheel cylinders.

 

had new 1 put on yesterday and he just bench bleeded the master cylinder ABS light came on. found a plug to master cylinder unplug when I got it home. I plug it in abs light went away. hour later truck would not move .wrecker took to shop had hard time getting on flatbed and to while get off wrecker . I started truck before we left. got to shop truck would not even start now. ty for reply

 

When you press the master cylinder with your brake pedal, the piston moves forward and pressurizes the hydraulic lines leading to the slave cylinders (calipers and/or wheel cylinders). There are two ports between the piston and the reservoir, the equalization port and the fluid intake/return port. Of those, the intake/return port is smaller and more likely to clog (that's the one I meant, not the equalization port), but if either of them clog, it can prevent the master cylinder piston from returning and leave your brakes locked (and cause the ABS to fail if the ABS actuator cannot make up for the overpressurization from the master cylinder).

It is not likely, but you may have gotten a new or rebuilt master cylinder with one of those two ports blocked. Stuff happens.

Questions:
1) Did you replace the master because it used to work well before, but now the brakes were not working? If so, how were they not working?

OR

2) Were the brakes not working because the truck had sat for a long time?

 

I drove truck till yesterday. my breaks was going way down almost to floor. I had already had front and rear breaks changed couple months ago. even new rear spring kits I had keep going back get rear break adjusted so they said it was master cylinder bad fluid little dirty master cylinder new from napa yesterday, no truck never set. been running good. till after new master cylinder was put in
now not starting since it came off wrecker.

 

well I found the shut off switch truck started up. I had truck tow back home
been at shop 4 days . still not sure why rear brake are locked up. any I deals?

 

had both rear wheel cylinder replaced today. wheels not lock up now. but I took it down road 4 miles rear both side was hot even smell it . new shoes back new pads on front new spring kit. what wrong ? ty

 

so I went for ride in truck I pulled e- cable few times in unlock wheel but brake pedal went close to floor I went 15 miles I got out felt rear cold. when I shut off truck restarted it. had a full break still feels like e brake is hanging up,

 

got truck back in shop and he gets 1 wheel to turn not other back them always out. he get 1 not other to turn. he takes out parking brake inside of drum. still 1 wheel not turning. someone must know? thanks

 

When I replaced my rotors and pads, I got everything done, backed out and drove around and my rear drums were smoking, smelled disgusting, couldn't figure out why. Truck felt like it was being held back, turns out I pushed the parking brake in and it didn't turn the parking brake light on and I was driving with the brake on. Sounded similar to your situation, so check if your parking brake is on or stuck?

 

not parking breaks
those was taken out drum still locks up no lights on in cab truck

 

we starting to think its the ABS Hydraulic Assembly. if you unplug the plug from the ABS Hydraulic Assembly will it disable it ?