Reservoir beside brake booster
 

Good morning. I ordered my new brake booster and master cylinder for my 69 C20 dually and while waiting I decided to spray everything I need to remove so it will come apart easier. Can anyone tell me what the extra reservoir is to the right of my brake booster. Unable to find any pics of other trucks with that in it. Thanks

Re: Reservoir beside brake booster
 

Hydraulic clutch?

Re: Reservoir beside brake booster
 

It is a 4 speed but I didn't think they had hydraulic clutch that early.

Re: Reservoir beside brake booster
 

It's likely a slave cylinder for the clutch - not a hydraulic release bearing like they have today. Look where your clutch actuating lever connects to the bell housing and see if you have a push cylinder rather than mech linkage. They had this setup as early as 1960, it used to be part of the main master cylinder. But, this setup looks like an old single pot brake mc (which would work for the clutch) from 63-66 trucks (and cars) - have not seen one on a 69.

Re: Reservoir beside brake booster
 

Since there's no line coming out of the old single port MC the clutch linkage has probably been changed to mechanical?

Re: Reservoir beside brake booster
 

It could be the master needed for a hydraulic trailer brake set up.

Re: Reservoir beside brake booster
 

Most likely answer. Look under the dash to see if there's a rod connecting this MC to the brake pedal.

Re: Reservoir beside brake booster
 

might also be part of a big truck set up