Leaking Hydroboost Brake Booster

Discussion in 'GM 6.5 Diesel Engines' started by bobbiemartin, May 21, 2010.

  1. bobbiemartin

    bobbiemartin Author of The DB2 Conversion Guide

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    The hydraulic brake booster on the Suburban is leaking, so I guess its time to replace it. I have been told to stay away from the rebuilds as they tend to leak soon after installing. Anyone have any experience with these or any tips on replacement? Thanks!
     
  2. whatnot

    whatnot Member

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    Where is it leaking?
     
  3. 625fireman

    625fireman I have injecter-itis

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    I have had good luck with Cardone.
     
  4. Burning oil

    Burning oil LeroyDiesel.com

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    I replaced mine using compression to flare fittings on the steel lines and stainless steel braid hoses. Im pretty sure I have pictures if wanted? I can also get a price if you don't want to DIY.
     
  5. dangerousdave

    dangerousdave Brain Damaged Diesel Junkie

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    I bought a seal set from MBM online. http://www.mbmbrakeboosters.com/Hydro-Boost-Rebuild-Kits.html
    They are wholesale to shops, but you might talk your way in...):h
    Kit 50 Hydro-Boost Repair Kit (Mostly Rubber) about $40 IIRC.
    I did it myself, not much blood, only a couple of cuss words.:rolleyes5:
    Be sure to flush the entire power steering and boost system before you start, to give the new seals longer life. I found a thread or two about this stuff around here before the DTR / TTS switch.

    If you don't want to DIY, there are "lifetime guarantee" units...:svengo:
     
    Last edited: May 22, 2010
  6. Steve93mustanglx

    Steve93mustanglx Diesel fanatic!

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    Rebuilt mine with an Auto Zone or Napa kit... 5 years ago. No problems whatsoever and easy to do.
     
  7. WarWagon

    WarWagon Well it hits on 7 of 8...

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    Autozone no longer sells the rebuild kits. Make sure you know what brake system option you have: the 1 ton system is more expensive.

    The star washer/retainer keeping the pushrod in on the unit is a pain. The rebuilds do not come with it. You need to move the washer up and down to get it free and out.

    The rebuild I got from autozone is doing fine so far. The don't make them new anymore.
     
  8. bobbiemartin

    bobbiemartin Author of The DB2 Conversion Guide

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    I've been away at a charity event, but I found a new AC Delco unit on eBay for less than $200 shipped, so its on the way. I hope to install it next weekend.

    Thanks for the replies!

    BTW, they are still available new from the dealer, but at a pretty high cost!
     
  9. WarWagon

    WarWagon Well it hits on 7 of 8...

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    Must depend on the year as 1993 is no longer dealer available.
     
  10. nealpellecchia

    nealpellecchia New Member

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    where is the guy who said last week that you don't have to take it out of the truck to rebuild it? I took mine out but the piston stayed with the fire wall half. It's attached to the pedal still. Un-expected. The pictures all show the piston and linkage separate from the the pedal eye hole part. I've read that some are sawed off others need a special tool to detach...Help? Or will it all come through the fire wall? But then how is it separated from the seal area so you can pull it out and replace the seals there, not to mention putting the piston back into the bore/ cyl? 714-915-1364 Neal
     
  11. 4thesporty

    4thesporty New Member

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    Replaced mine with a Cardone rebuild about 4 months ago. Easy.

    One tip though, make sure you have a gear wrench and a deep socket for the four bolts holding it to the firewall. (15MM IIRC) I fought and fought them with a box end, and it can be done, but at about a 1/8th a turn at a time. Gear wrench is perfect though, and a deep socket for the two you can get at with it.

    If you have never removed your brake light switch before, that can be a bear sometimes too, and must be done for this procedure. I am not sure of the cutoff year, but mine was fairly easy as long as you don't lose the retainer clip. Some of the later year models came with a diffrent retainer that was mostly destroyed upon removal and should be replaced.

    As others have said, do a good flush while you have all the hoses loose, it is easy and only takes ~10 minutes to do with a helper.
     
  12. Brooklyn Tow

    Brooklyn Tow 9 11 Never Forget

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    Replaced mine when I bought the truck....(Gotta be more than 5-6 years ago) with a rebulit unit, not sure of the brand, but she's still going fine...
     
  13. nealpellecchia

    nealpellecchia New Member

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    OK, I decide that if the spool valve is a machined fit back into the housing then a soaking wet piston can be put back into a machines bore with a new seal and no special tools. Well it wasn't as soaking wet as I would like to have made it but I didn't want to drop it like our Dr. almost dropped my son at child birth.

    I didn't have to destroy the brake lite switch! I just decided to use that as the decisive factor in getting it back in and avoided it. I hooked the spool valve to that piston connector, centered the unit with the bolt pattern, and started inserting screws to pull it where it needed to go! The fear and perfectionism of those piston surfaces had to take a back seat to common sense. Are you listening Washington DC? The key is that putting in a rebuild requires pulling the whole thing out under the dash. That seal wasn't leaking for me and most of you. you have to cut the cable once you get it out so you can pull the piston and reinsert it like a good boy with a special tool that does who knows what! Then you need a separate kit to reconnect a cable to the brake pedal. So if you got the nerve to do open heart surgery and that's what it's like, to save money spending only $25 for a kit instead of about $150 for labor and an avg. of $150 for the part: then do it. I'll talk you through it.
     
  14. chefmike

    chefmike Not just a truck... a project.

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    I was in Asheville a few weeks ago and stopped in at MBM, the company that makes the rebuild kit. Really nice folks. They were totally happy to sell a kit over the counter, so if any of you all are looking that direction, give them a call.
     
  15. nealpellecchia

    nealpellecchia New Member

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    yeah and he even called me back to tell me how to make a special tool too put the final spring retainer on in the front!! couldn't have done it with out it.
     
  16. ak diesel driver

    ak diesel driver Active Member

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    please post contact info for MBM
     
  17. chefmike

    chefmike Not just a truck... a project.

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    David Ziller is the accounts manager (david at mbmbrakeboosters.com) 800.231.4125 x107
    He said he would be more than happy to sell kits and could set up a dealer as well.

    mbm brakes

    The 501 kit on the bottom is what they recommended. It has that star washer that Is key somewhere in the process. They have a pdf of the rebuild here

    I choose not to go this route, as it looked like more than I wanted to curse at. I am not intuitive when it comes to this stuff and $200, though expensive, seems worth it. Mine is still leaking, as I have yet to tackle the job. Looks like a pain to get to the brake pedal. I guess you can drop the steering column retaining brackets to make it easier?
     
  18. ak diesel driver

    ak diesel driver Active Member

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  19. 4thesporty

    4thesporty New Member

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    It's not that bad as long as you can contort your body under the dash :)

    Like I said earlier, just get a gear wrench for the four nuts on the firewall. They are all locknuts and are very long winded. I retrospect, when re-installing mine, I should have got regular nuts and some lock washers rather than fighting the nylocks all the way down those threads, or just cut half the threads off.
     
  20. dangerousdave

    dangerousdave Brain Damaged Diesel Junkie

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    It wasn't that hard, I took the hood hinge pivot bolts out to raise the hood vertical. I also only replaced the leaking seal, not the whole kit.
     

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