How to repair a leaking Hydro-boost unit

Repair your leaking Hydro-boost unit for way less than the cost of a new one and it can be done by most people in an hour or less....and you do not need to remove the whole unit from the vehicle.

[@lakeviewgarage3103]

Great video on repairing the leaky hydroboost. Thanks for making it so we can help keep our older rigs alive.

[@BruceCoggins]

Thank you...yes it is an easy process and saves you a lot of time and money.

[@noonergarage4114]

Thanks for the tips and video. Worked great for my 1993 GMC dually. 🙂

[@ronsmith7527]

Yours is definitely the best video on this. I don’t understand how we avoid rolling the lip of the new seal since the whole assembly goes on over the cylinder and it’s not tapered. Apparently it’s not a problem since no one has mentioned it.

[@BruceCoggins]

Thank you and you bring up a good point...I've often thought about that when rebuilding these but never had it happen. I always oil up the seal so maybe that's why it seems to slip on there.

[@jeffmunger]

Thank you for the video. Going to be doing this soon. Your neighborhood has almost as many dogs as mine :)😂

[@BruceCoggins]

LoL, thanks. I think my neighbors bought a new dog for each of their kids and they like to walk them around my cul de sac about once a week... annoying LoL

[@jamesmills4175]

very nice looking truck.

[@BruceCoggins]

Thanks 👍

[@65mrcarguy]

Good video. Beautiful truck!

[@BruceCoggins]

Thanks 👍

[@chrismadaj8751]

Nice should could've seen this first GODSPEED

[@shep145]

The seals are notoriously hit and miss in quality. I used the Amazon ones but it still leaks so I get to do this twice. :)

[@BruceCoggins]

Exactly, the seals you get today aren't as good as they used to be. One trick that works is to pack the seal with grease before you install it. That's something we use to do years ago. Try that and see how it works for you.

[@papergatorzfedducca7998]

Do you think the master cylinder will cause all 4 brakes to slightly drag? I can release each one when I open the bleeder screw. Once I drive it for about 3-7 minutes it starts back dragging. I say slightly dragging because I can jack up the truck and turn them by hand with a lot of force. No leaks on the master cylinder or hydro boost. I’ve greased slider pins, bleeding the brakes 3 times, topped off the fluid on both power steering and brake fluid. Power steering is making the whining noise. It’s a 2004 Suburban with hydro boost system. Please help.

[@BruceCoggins]

Disc brakes do have a tendency to slightly drag but the wheels should turn freely when you spin them by hand. One thing you can try is loosen the nuts holding the master cylinder on the booster and see if you can feel the rod pushing it away...if it does then the rod is too long or the pedal isn't returning all the way. It shouldn't cause all 4 wheels to drag because as you push the brake pedal the fronts activate first and then the rears.. or vice versa but either way only one or the other will be in play. As far as the whining noise in the power steering, as soon as the bubbles disappear the noise should go away. Check the ps fluid with the engine running and add as necessary.

[@papergatorzfedducca7998]

@@BruceCoggins ok thank you I’ll let you know how it goes tomorrow!!!🔥🔥🔥

[@papergatorzfedducca7998]

@@BruceCogginsnew subscriber 🔥🔥🔥

[@HallnoutMhall]

Did you figure out what your problem was then?

[@papergatorzfedducca7998]

@@HallnoutMhall master cylinder.

[@XroorX]

What is The 350psi cylinder called? On my 2006 it has “BAS” something g on it. Thanks

[@BruceCoggins]

It's an accumulator. Once you separate the two halves it is easy to compress the accumulator with a large C-clamp so you can remove the c-clip holding it in. There is an O-ring on the outside so just replace that. Do not try to compress the piston to get it apart. If the piston is collapsed then you should be able to order a replacement from eBay.

[@XroorX]

@@BruceCoggins thank you so much for the reply. Bought the truck with only the REAR lines replaced, then had mechanic replace the fronts….then, he only tries to bleed the fronts…. So I paid him and he split. Now, the cylinder is making a slight goose sound when I depress the brake…engine is mint, interior is mint, now I’m understanding why guy only wanted $2k

[@youmarcop]

I would know what part was booster leaking? My problem is between booster and master cylinder

[@BruceCoggins]

Once you pull it apart you will see the figure 8 gasket and then there is a seal in the bore...I show this in the video. Replace those two things and reassemble

[@tanakahege3551]

What did do wrong, my breaks are locking up

[@BruceCoggins]

There are a few possibilities...the rod behind the master could be installed wrong and it is activating the master at rest.To check this, loosen the master and see if it pushes away from the mounting area. Are the front brakes locking up or the rear?

[@tanakahege3551]

@@BruceCoggins front Brakes.. thank you kindly for your response.. I will work on it again over the weekend.. the pedal goes down a notch when start the truck up and based on your response I totally agree

[@tanakahege3551]

@@BruceCoggins the rod you are talking about is it the one with the spring or the one you have to line up from the inside

[@busher69]

Good video but with today's trucks engine bay being stuffed with horse hockey, I'm taking the assembly off except for the master cylinder.