Who here has hydroboost?? I just swapped my 97 f250 with a used unit from a 97 f superduty... New power steering pump with 2 return ports.. I moved the pin on the brake pedal up towards the pivot.. Used my master cylinder- just widened the mounting holes. Took for a test drive and my brakes are locking up.. I limped home and loosened up the master to booster and it worked. Not sure where to start Any ideas??

 

Pretty sure you have to modify the brake rod but I don't remember how much I did it years ago

 

I did exactly what you did with my 96 F250, except I bought a new,or maybe it was a rebuild, 97 SD Motorcraft hydroboost and mine worked perfectly. The new hydroboost came with the rod that goes between the booster and the master cylinder already installed. I remember that the old vacuum booster rod had a threaded cap on the end that was adjustable for length. The new hydroboost rod was just a rod with no adjustability. The new hydroboost came with a note that said something like "Don't even think about removing this rod." I didn't remove it and don't know why they provided the warning and what the consequences are supposed to be. I think I've read posts from guys who removed it and put it back without the sky falling.

I read at least 500 million threads on SD hydroboost upgrades before I did mine and I don't recall anyone having locking up problems.

I'm trying to think if anything else like air in the system, either the hydraulics from the steering pump, or in the brake system could be causing it to lock up? By locking up do you mean extremely sensitive, or do they actually lock up and stay locked up?

Very disappointing not to have things work and I hope you get this figured out soon. The hydroboost is one of the best mods I've done so far.

Bob

 

Haven't messed with it besides cleaning up my mess and shut her down for the night.
My test drive consisted of me going around the block. I brake checked on my street and damn near put me into the windshield "wow" this is awesome!!
But the further I got from home the more they started dragging..

 

It is what has been mentioned...you would have to purchase a new unit to get the correct rod, you cannot use the one from the vac booster as it is too long. There was a write up, many years ago, where a member made his own and gave the exact length. You cannot get the rod separately. Hope this helps some

 

Any update? Hoping that no news is good news and you've got it sorted out.

Bob

 

Yes I meant to log on this morning.. Last night I picked up a master cylinder from Napa part number NMC M3240... On the thought that I would start the parts changing process the cheaper way... And that did the trick! This master is new and has the cruise control provision and comes with reservoir. Thank you to all that responded