'04 Green Horn

I have an '04 3500 with the 5.9 Cummins that I bought two weeks ago, after 5 days of driving it my front brakes locked up completely when I tried to pull away from a traffic light, they would not release. I let the truck set for two hours and the brakes seemed fine after that until today which has been 6 days later than the first brake issue. Today I was driving home and the brake pedal went all the way to the floor and would hardly stop the truck. I made it home and when I was backing into my driveway the brake pedal started working like nothing was wrong again. no warning lights coming on the dash either. I am thinking brake booster, but I am no mechanic so any help on this would be greatly appreciated.

BigIron70

Check your brake lining thickness make sure that's ok. Check brake fluid level is it empty? Look at cap seal is it swollen if it is possible contamination. Jack front end off ground and check for excesive play in wheel bearings. Put pressure on brake pedal if it slowly sinks to floor most likely master bad.

dozer12216

Sounds more like the hydroboost unit is going out.

'04 Green Horn

Since no one has anything definitive I am going to change out the master cylinder tomorrow since it is the cheaper of the two. I appreciate the input and will post what I find after the repair.

'04 Green Horn

Well I replaced the master cylinder this morning and have been driving the truck all day with no problems. I'm not totally convinced I am out of the woods yet, but again so far so good.

cameroneod

Hows the steering?

volly818

Had the same problem with my 1500. Front brakes would not release then would be fine for weeks. finally the pedal had to be pumped at every braking. Replaced the master cylinder and all was good. I think you will be ok.

dodgge1ton

the flex brake lines are bad had it happen twice

'04 Green Horn

The steering has been fine the entire time. The brake fluid before the master cylinder change was very dark, almost burnt looking. I put new fluid in along with the new master cylinder and so far so good.

Thanks for the info to all that has posted.