ok im trying to covert my vacuum to hydroboost but ran into a litle problem.i have a 2006 silverado ss 2wd with rear drums.my problem is the hydroboost wont bolt up to my mastercylinder.would i be able to use the mastercylinder that came with the hydroboost with no problems?? has anybody done this?? dont the rear drums run at a different pressure,hydroboost is off a 05 escalade..... thanks in advance.....

 

subing to see outcome. but you have to use master cylinder from hydroboost. notice how small it is, it doesn't use van anymore. and i believe the propositioning valve is further down the line and isn't bothered by this swap

 

so the swapping of the mastercylinder would be ok without changing anything else??

another problem i ran into was i had to trim about 1/4 inch of the top of the firewall as the locking bolt on the hydroboost plate was hitting the firewall not letting it sit flush. no big deal i used a grinder and took about 5 min......

 

Am I crazy or does the 05+ RCSB truck do not have a proportioning valve from the factory? Over Christmas break I am swapping to rear disc and hydraboost. My other trucks all have a factory proportioning valve right under the master clylinder.

 

When the hydro-boost swap was first detailed, the master cylinder was part of the swap. It wasn't until later that some guys found out that, in some cases, the master cylinder they already had would bolt up.

The bolt spacing for the master cylinder changed at some point. I suspect its when GM started using the drum brakes in 05. The bolt spacing was different between my 2004 ECSB and my 2006 CCSB, both 1500s.

 

The reason why I ask is because my master cylinder is way beefier than a 05 and under.just making sure mine doesn't operate different due to the drums....

yeah i dont see the proportioning valve either,i wonder if its build-in my mastercylinder!!

 

ttt......

 

If the prop valve isn't in the engine bay below the master cylinder it is most likely built into the BPMV/EBCM aka your ABS module. So you should be fine running the escalade master cylinder.

 

ok cool thanks

 

I have seen the hydroboost setups with 2 different size of master cylinders, depending on the year. Might be easier to find a different year to match your setup