HYDROBOOST BRAKES

[KR69IDI]

I've noticed that a few members have done the hydroboost conversion. I'm interested as well and would like some feedback on how those who have done it are satisfied with it. My master cyl is going out, so may as well upgrade if I'm changing parts anyway!!

 

[Full Monte]

I like it very much. Truck 1 in Signature was scary to stop with the vacuum system. I could never get it working properly. Having a very heavy rig with camper just was too much for it. I doubt if you'll hear anyone who has made the changeover to hydroboost say that it didn't help a lot.

 

[MIDNIGHT RIDER]

Believe me or not, I just was speaking with a guy whose truck came factory equipped with Hydro-Boost brakes.

He was showing me how he had removed the hydro-boost and had installed a vacuum system off an older model.

He said that, once he got the hydro-boost off, he threw the whole mess as far down in a holler as he could sling it.

He said that he was fed up with poor braking performance, that his brakes had nearly gotten him killed for the last time, and that the vacuum-booster would stand the truck on it's nose.

I could hardly believe what he said; although, the evidence of his convictions were right there in the form of an older system swapped in.

My own experiences with hydro-boost brakes, factory installed--not conversions, are just the opposite; hydro-boost brakes will throw you through the windshield, if you ain't hanging onto something.

I can't help but wonder what was so wrong that he gave up on his.

 

[icanfixall]

This guy probably "fixed" something that was wrong with his hydroboost system when he changed it out to vacuum and didn't know he had done something. The hydroboost will almost double the pressure available at your foot.

 

[towcat]

Believe me or not, I just was speaking with a guy whose truck came factory equipped with Hydro-Boost brakes.

He was showing me how he had removed the hydro-boost and had installed a vacuum system off an older model.

He said that, once he got the hydro-boost off, he threw the whole mess as far down in a holler as he could sling it.

He said that he was fed up with poor braking performance, that his brakes had nearly gotten him killed for the last time, and that the vacuum-booster would stand the truck on it's nose.

I could hardly believe what he said; although, the evidence of his convictions were right there in the form of an older system swapped in.

My own experiences with hydro-boost brakes, factory installed--not conversions, are just the opposite; hydro-boost brakes will throw you through the windshield, if you ain't hanging onto something.

I can't help but wonder what was so wrong that he gave up on his.

care to elaborate what year make and model his truck is?
GM had hydroboost since 1973 on the 1 tons and on all diesels.
Ford has hydroboost on f450's and on up since 1988.
I'm not sure about dodge's tho.
One thing for sure is the fact that hydro does act lke a slightly different animal compared to vacumn brakes. When you have a aging hydro system, there is a slight lag between the time you stand on the pedal and when the boost catches up. When it does, whatever isn't tied, bolted or straped down, is going to go through your windshield.
What it sound like to me on the guy who tore out his hydro is that the unit has lost it's braking power on a panic stop but wasn't leaking yet, so he "assumed" that the unit was operational but "defective". I would consider his experience as an indication that the unit was wore out and needing replacement but not defective.
I'd hazard to say that everyone who has installed hydro here has some pretty positive things to say about it.

 

[trackspeeder]

Very satisfied with it. Converting the 90 F350 next.

 

[7.3shrk]

converted my 85 GMC to hydroboost and rear disc brakes...locks 36 inchers up without a problem and stops on a dime. I love it and am doing my f-250 next.

 

[KR69IDI]

Thanks for everyone's input. This sounds like a no brainer to me. I've never been impressed with the factory vacuum assist anyways. I doubt anybody has!!!

 

[Dirtleg]

I'm going to go out on a limb here a little bit and stir the pot. First I will confess I have not driven the Ford hydroboost setup. There could be something I am missing.

The H2 has the GM hydroboost setup on it and I think it has poor braking at best. Has since day one brand spankin new off the lot. This I believe to be a function of the brakes themselves more than the method of assist.

My 93 F350 has damn good brakes with the vacuum assist on it. Not that I believe the vacuum assist is the shining star here just more a result of the brakes capability when everything is working properly.

My 87 BMW has a hydroboost system on it also. It has the brakes off a later model larger BMW and stops really well. Again the method of assist is seamless and allows the brakes to do their job.

What I am getting at is that a correctly functioning assist, be it vacuum or hydraulic, will allow your brakes to work at their full potential. If your vacuum assisted brakes are less than impressive make sure it's not just poor brakes before deciding that the hydroboost is the answer.

I know the argument is for safety in the event of vacuum pump failure. What failsafes are built into the hydroboost setup in the event of power steering fluid loss/pump failure? On my BMW there is a reservoir/pressure accumulator that allows the brakes to be applied 6-10 times before losing assist in the event of hydraulic failure. Is there a similar device on the Ford hydroboost setup?

I'm not trying to ruffle anyones feathers here just had some opinions and questions I thought I'd share.

 

[KR69IDI]

Dirtleg, I must have more issues with my truck than I previously stated. For some background, I've had this truck for about 5yrs. Honestly I've only driven it about 5K miles in that time. I've replace 2-3 vac pumps in that time and it seems that whenever I put a new vac pump on then it stops fine for a few months and then back to very soft pedal. I'm getting real interested in getting this truck on the road more due to this site, but I need it to stop when it should, especially when pulling heavy trailers. So it seems that now I may need some advice. Any help very appreciated!!!!

 

[Dirtleg]

If you have a soft pedal I would lean more towards;

Air in the lines. Bleed the brakes. If air continues to get in there is another issue. Look for a leak.

Water in the brake fluid. Brake fluid is hygroscopic. If you haven't flushed the fluid out in the past year or two you could have enough moisture in the fluid to cause noticable brake fade or a soft pedal on hard stops.

Worn master cylinder. The master cylinder could be bypassing brake fluid internally past the piston seals as you hold the brake pedal causing it to get soft.

If you were losing vacuum, and consequently the assist it provides your pedal effort would increase.

 

[KR69IDI]

Thanks Dirtleg, that makes sense. I'll start with your ideas.

 

[MIDNIGHT RIDER]

A good simple diagnostic test is, with the engine running, apply the brakes firmly and keep adding pressure to the pedal.

Does it stay there firmly ??

Then the problem is not with the hydraulics.

Does it slowly sink toward the floor ??

Then, you either have an internal master-cylinder leak with no noticable decrease in fluid level, or an external line, or wheel-cylinder, leak and be losing fluid from the reservoir.

Does it push back at you, not letting you press it down quickly??

This is hard to explain; but, a sure sign of a ruptured diaphragm in the booster is that, when you try to apply the brakes, it is like the pedal is trying to fight back at you, sort of an intermittent reverse pressure against your foot on the pedal.

To track down bad brakes, start at the rear wheels and work toward the master-cylinder.

Most braking complaints can be fixed with a good adjustment of the brakes.

When the shoes are too far out of adjustment, nothing about the system will work as it should.

 

[7.3shrk]

Even with the brakes working fine, it casn slowly sink to the floor though, as the vacuum pump builds more vacuum.

 

[82fordtruck]

This ceertianly isn't too scientific, but my GMC with hydroboost will stop faster than any ford I've driven.

Damn good hing too - because it goes faster as well.