I have read lots of your postings over the past year or so. I have had a 99 SD 7.3 and loved it...no problems. However, now I have a 93 F-350 4x4 7.3 dump. I am haveing trouble with my brakes. I have changed the MC, new calipers/pads on front, new shoes on rear. I have good pedal when adjusting with engine not running, but when start truck the pedal will go down significantly and if i pump it... the third pump........no brakes, but, pedal. Any ideas???
Thanks

 

I think you might have to take it to the dealer. You need a computer to adjust the ABS system correctly. just my.02 worth.

 

Sounds like you are running out of vacumm.
Diesel use electric or mechanical vacumm pumps for the brake booster. You may have a leak in the vacumm tank/lines or a pump going bad.

 

Same exact thing happened to my '97....replaced the vacuum pump and the problem went away...make sure you buy a new pulley with the pump!

 

Another vote for vacuum problem. I would check into the vacuum hoses first then the pump then the booster. If you pull the hose off the brake booster and put your thumb over the end with the engine running you should feel significant vacuum.

As for the pump, you can get them at AutoZone, NAPA - any number of places. I got mine from a Ford/Sterling truck dealer due to a breakdown on the road. The auto part houses can pull the pulley off the old pump and install it on the new pump for you. Many have a "loaner" program - you buy the tool, use it then return it for a refund.

If you do the pump, when you reinstall the pulley on the new pump make sure all the bolts will go into the mounting ears with the pulley in place. On mine (1995) there is one bolt that will not come out of the pump with the pulley mounted and, therefore, must be in the new pump before installing the pulley. You will see when you take the old pump off if that is the case on yours.

Dave / Believer45

 

how would an electric vacumm pump work over a mechanical one

 

I could be wrong, but I am pretty sure a 93 F-350 4x4 7.3 dump bed (chassis cab) doesn't have ABS. I think in 1993 the F-150 might have come with only front ABS.