1999 K2500 Suburban - Hydroboost leaking, replace or upgrade?

[TexasAggie]

Found a pretty significant leak on the hydroboost unit in my '99 3/4 ton Suburban yesterday. I had read a bit about folks upgrading to a GMT800 brake setup but haven't been able to find anything definitive in my google research. Most of what I found is half ton upgrades from vacuum boost.

Is there any advantage to upgrading to a GMT800 booster and master cylinder if you don't upgrade calipers and drums at the same time? My current setup works well, but any improvement in pedal feel and stopping power would be a nice bonus.

If I missed a thread that covers this specific question, send it my way!

 

[stutaeng]

I don't know the answer to your question. But I replaced the hydroboost on my 00 K3500 when I bought it with same unit, remanufactured.

I forget what the K2500 SUVs got for brake codes. I "think" it's different than the 3500 SRW? Maybe that's another option if they are different? Or rear brake components?

Lastly, you've seen that video from Lawrence Tolman on his YT channel where he does the GMT800 front brake upgrades, right? It's been posted a few times somewhere here...

 

[RichLo]

I have heard that unless you put disks on the back, the GMT800 upgrade is not recommended.

 

[TexasAggie]

Lastly, you've seen that video from Lawrence Tolman on his YT channel where he does the GMT800 front brake upgrades, right? It's been posted a few times somewhere here...

I haven't seen the video. I'll look for it.

Where do I find the brake codes?

 

[stutaeng]

Glove box RPO codes. I think I posted that video at least once, let me find it...

Here you go:

GMT 800 front brake upgrade to GMT400 8 lug

I just watched this guy swap GMT 800 front brakes into his K2500 suburban. I honestly didn't realize it was that difficult.... Towards the end he mentions a hydroboost master cylinder upgrade from the big, heavy 10 lug 3500HD GVWR 15,000 trucks. I may decide to do this to my K3500 beater, LOL...

www.gmt400.com

Has additional information you may find useful on that thread.

 

[GoToGuy]

Where is your leak from brake fluid side or hydra power side?

 

[TexasAggie]

The booster is leaking power steering fluid. It's coming from underneath on the backside somewhere (not the lines).

 

[Schurkey]

Isn't that the "fix" that you leave the Hydroboost attached to the firewall, then remove only the front part of the Hydroboost unit, and replace an O-ring? In other words...easy?

I've never done it, but there's YouTube videos.

 

[TexasAggie]

Isn't that the "fix" that you leave the Hydroboost attached to the firewall, then remove only the front part of the Hydroboost unit, and replace an O-ring? In other words...easy?

I've never done it, but there's YouTube videos.

I'll have to look into that! The leak is getting worse, so I need to get after it in the next week or so (not a daily driver, but have a trip coming up). If I do have to replace the whole thing, how difficult is it? I was looking up under the dash and really can't see anything. I would imagine getting to the bolts is the hardest part.

As far as the master cylinder goes, can you leave the brake lines connected and therefore not have to actually mess with the brake system at all (other than unbolting the master from the booster)?

 

[stutaeng]

You can remove/replace the hydroboost without messing with brake hydraulics. When I replaced my hydroboost, I was trying to figure out why my brake lights weren't working and changing by brake light switch. I had dropped the steering column. Not sure if that's necessary for doing the hydroboost...

@Supercharged111 posted the procedure on replacing just the seal on the hydroboost on one of his threads recently. It's much less money to replace just that internal seal, and less work also.

Master cylinder will require brake hydraulics bleed and all of that...