Re: 196? GMC 4000 B-model
 

No, you need one for the bigger truck as there is a 3rd line the runs down to the brake boster.

Re: 196? GMC 4000 B-model
 

oh alright, thanks. This rebuild lot says it fits, any thoughts?



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Re: 196? GMC 4000 B-model
 

I can't say I have not had one apart for either size of truck.

Re: 196? GMC 4000 B-model
 

Well I removed the master cylinder and its severely rusted/pitted so I've been looking for a replacement and the only one i could find with the aux port to the brake booster was a Bendix 11201 Master Cylinder. Still have to double check the bore sizes but it looks like the best choice for the bigger trucks.

Re: 196? GMC 4000 B-model
 

Just bought a ''big truck'' cluster. Does anyone know how to hook up the vacuum reserve gauge? I'm assuming it goes to the vacuum tank? Also where to find a tach assembly I haven't been able to find one.

Re: 196? GMC 4000 B-model
 

The tachs come up on Ebay every now and then. Sometimes they're stupid high but just as often someone will price them about 50-75.00 shipped

Re: 196? GMC 4000 B-model
 

I think I worded that poorly. I have the Tach gauge, but I don't have the tach cable or the camshaft take-off that's what i'm looking for. Or was that what you meant?

Re: 196? GMC 4000 B-model
 

The vacuum gauge on the big truck cluster is for the Hydrovac brake booster so in your case if it's going to be used in a light duty truck in won't work for that purpose. You can just hook it up to manifold vacuum as a mileage minder type gauge. The tach drive parts are definitely something you're going to have to search for, I've had a few of these in the past but have sold them off to other members but hopefully someone on this site has the stuff. There is a fitting that screws to the back of the cam then attaches to the tach drive so make sure that's included. As for whoever mentioned a tach for $50-$70 you're way off unless it's just a standard Sun RC-50 which resembles the GMC/Sun RC-5A. The RC-5A has the GMC style block numerals you won't find one of these for less than $300 and most won't include the transmitter box. I've seen some real outrageous prices on these tachs recently on ebay ranging from $450-$600.

Re: 196? GMC 4000 B-model
 

Here's a photo of what you're going need. Maybe someone parting out a big truck will have it.

Re: 196? GMC 4000 B-model
 

well I have a 4000 with the hydrovac so do you know where/how its setup? I got the whole cluster for $35 so not bad In my book.