The Stovebolt Site Forums The Parking Lot Big Bolts 1946 1.5 ton vacuum system

I have a 1946 1.5 ton that I bought half restored and I am in the process of finishing the restoration. I have always wanted a truck like this but I am new to some of the concepts of these trucks. The Vacuum system lines have been totally removed, but the compents are there, the vacuum assist on the fuel pump, brake booster, winshield wipers, and a two speed rear end. I was hoping that someone has a diagram or a schematic of the lines for the system. I am close to finished withe the truck but I am unsure of how to reassemble the vacuum system. any help will be greatly appreciated. Thanks!

gmc has an intake manifold that has one to three ports on it(depending on vintage) that screws into the intake manifold on the engine. one port is for the hydravac, one for the two speed rear and one for the wiper. that fitting came off a 46 350 and is on my 40. the ashton is a little different. it has a fitting that screws into the manifold then a hose goes from there to the firewall where there is a manifold there for everything you desire. all you really need is a fitting and vacuum hose to get from the engine to the firewall to make your connections.

Can I run the two speed rear end, brake booster, and wipers off of just the intake manifold or do I need to connect to the vacuum part of the fuel pump also? I feel like something needs to connected to the fuel pump, but I may be wrong. I may need to do some more digging on my truck also, as I said I am very new to these trucks, I think that I may be missing the manifold that you say should be on the firewall.

thanks for your assistance.

Hi jdchevy. I just discovered today an expert on the brake systems from 1910 to 1960 models. He has the parts and also rebuilds them. I think his company is Midwest Power Prod. He is in Morris, Illinois. His name is Rick (super nice) Phone: 815-942-0550
He is sending me a new Hydrovac for my 57 GMC LCF 2 1/2 ton.
Price was cheaper than rebuilding mine.
Wayne.

Thanks for the tip,OLD GMC Gold!! There's ALWAYS a "Big-Bolter" out there,looking for a decent price on a hydro-vac! I may be looking for one,myself,this Spring. Depends on if I can find a re-build kit,or not. I'm writing this info. down,and keeping it in a safe place! About once a month,(at least),someone's looking to re-build/purchase one. Thanks,again!! BIG HELP!! B.T.W... Any pic's of your '57? Let's SEE the "GOLD"!

Welcome to the "Bolt",JD CHEVY!!Now back to the TOPIC! If you look at "Page 3",in my "Photobucket" link, you'll see my truck sitting there with the headlights,and grill removed.You'll also see my shadow holding the camera. This video SHOWS you how the plumbing is set-up for the 2-speed,hydrovac,and the wipers. the main-line attaches at the base of the intake-manifold,directly under the carburetor. I needed to add a T-fitting to mine,since I didn't have the origional 2-speed vac. switch,(which I believe, for the T.F. big-trucks),is mounted on the side of the transmission. I just ran one line to the 2-speed switch,(that you'll see mounted to the fire-wall),and the other line is plumbed to the hydrovac. If you need to plumb a line for your wipers,I'd think that you'd want to install another T-fitting into the 2-speed side,since it doesn't get used as frequently as the hydrovac. If I'm wrong,someone with more experience than myself,will jump right in here,to help us both. Where are you in WISC? I Go to Prairie Du Chien,quite often,to visit relatives. Do you have any pic's of your '46? We'd ALL LOVE to see 'em!

you need to find a manual of some sort. without it you'll learn things the hard way. the fuel pump you describe is this i think http://www.oldchevytrucks.com/cart/product.asp?prodid=ME222&i=10317||||| not sure how effective they are. this site should help you identify what you have http://chevy.oldcarmanualproject.com/1929_54chevyparts/index.htm

I have some pics of the 57 on photobucket. But Im not very good with posting.
How do you get your Photobucket link to show with your posts?

I TRIED by following the instructions "here",in "The Short Bus" thread. I couldn't get my photobucket link to work,either,but,THANKS to "Worker-Bee" Peggy M.,she jumped right in there to get it linked for me. Sorry,but I'm still not sure how it works. If you try to link it,maybe someone will help you with your link. WE ALL Love PIC'S!

I just got off the phone with Rick from Midwest and I can add that's he's very nice and spent 15 minutes answering all my questions. I asked for my unit to be sent out bare metal (normally they paint them as part of the rebuild and he was more than happy to accommodate my request.

I placed an order for a rebuilt 'vac for a VERY good price.

So double thumbs up for Rick and Midwest Power Products.

Fast service too. I recieved my Hydrovac today! Its identical to my old one, that was not rebuildable (too rusty).
Its BRAND NEW, not rebuilt. All the parts stores and suppliers told me there was no such thing as a new one.
I hope I did the right thing. I posted his number without thinking to ask his permission.
Wayne.

When I spoke with Rick he did ask how he heard of his shop and I told him Stovebolt.com.... so maybe he's been getting some business?

My vac should be here next week. Was less expensive than going through my regular MV parts sources.

I found him by sending my HV to Brake & Equip. Warehouse in Mpls. Mn. for a rebuild.
They called me and said they had sent it out to another rebuilder. In turn he calls them in Mpls. and tells them to have me call him, because mine was borderline rebuildable.
So I call Rick and he sells me the NEW one cheaper than a rebuild.
I just hope he needs the buisness. I got to thinking I did not have permission to publish his name and phone on the internet.

He has a web site, so it's not like he's hiding

http://midwestbooster.com/

WOW! How did you find his site? Don,t guess he is mad at me then.
The guy at Mpls. led me to think he was sort of a one-man operation.
Looks like he has everything we would ever want in brake components. I am putting this info. in my safe!

Now an update on my project: I HAVE BRAKES ! On the 57 gmc 370. Got them bled yesterday.
This is probably the first time its had brakes in 20 years. EVERYTHING was replaced, except the original banjo bolts and fittings. Bad news is I have one leak at the fittings to the top wheel cyl.at the left front wheel. Gonna have to remove and try to find the problem.
After bleeding I have about half of a pedal without engine running. Is this normal? I was hoping for a full pedal, but this thing has 8 wheel cyls. Have not tried it with booster hooked up, waiting for a fitting to connect the vacum to it.

Are your shoes adjusted up tight, if not that could be the reason you get half a pedal.

Mike B

I will re-check them. Thanks.
Am I correct that when the booster is hooked up, the pedal will go down more?

Let us get back to the original subject of this thread.

If you have a dual action fuel pump, the vacuum assist is designed to provide vacuum for the wipers when the engine vacuum is low. This is usually when going up a hill with the throttle wide open. The pump assist provides the best assistance when the rpms are up. At low rpms and high engine vacuum, the pump provides less vacuum than the engine and the engine vacuum pulls through the pump. The draw side of the pump should be hooked up to the wipers and the other side connected to the manifold.

Yes you will have a little more travel in the pedal when the booster is working.

To test the booster turn thr engine off, pump the brakes a few times to use up any stored vacuum, then step on the brake pedal with medium foot pressure and start the engine. If it's working you will feel the pedal fade away a little as engine vacuum builds back up.

Mike B

Thanks for the info.

Wayne.

ive been doing business with rob for all my resleeving of wheel and master cylinder work. he gets two thumbs up from me.