Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

I'm adding a factory Delco/Moraine brake booster to my 1970 C/10 as part of a front disc upgrade. I'm trying to hook up a vacuum line that will look as stock as possible.

My truck as a 307 and a stock 2 barrel carburetor. I've read on other threads that the port on the booster hooks up to a vacuum port on the back of the carb. Is that just on four barrel carbs?

If so, does it hook to the port at the back of the intake manifold? I always see a rubber hose coming off the booster in photos here on the forum. Does anyone have pics of a 307 with a 2 barrel and a factory booster so I can see what parts I need to get?

This is my booster.

http://67-72chevytrucks.com/vboard/a...1&d=1427045336

Here's a pic showing what looks like a hard line coming out the back of the carb (not my truck or pic).

http://67-72chevytrucks.com/vboard/a...1&d=1427158791

And here's a pic showing the long rubber hose I mentioned (not my truck or pic).

http://67-72chevytrucks.com/vboard/a...1&d=1427161789

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

Not sure about 67, but all mine have a hard line with a flare fitting on the back of the carb that the soft line hooks too.

Much larger line than just a vacuum line. Should have same line ID as the connection on the booster.

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

Not going to say it's 100% right but it's what my 67 has with a 350 small block. I've seen several look like this though.:chevy:

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

ANDY----I'd replace that fitting in the manifold and get a brass 90 degree fitting in 3/8'', change the hose to an 11/32 like the factory has along with an updated filter inline. The filter is a brake booster filter---supposed to keep gasoline vapors from getting to the rubber diaphragm in the booster. Running the hose you have there through the 1/4'' nipple for the automatic is a no bueno

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

The truck is a 4 speed granny 1 gear. Never seen a filter on a brake booster line on these model trucks. I will check into it though.
Do you have a link for the fitting in the intake are the filter?:chevy:

https://www.grainger.com/product/6AF...P7A1P:20501231

https://static.grainger.com/rp/s/is/...536&$adapimg$=
https://shop.advanceautoparts.com/wc...5_pri_larg.jpg

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

Filter looks correct--can be had at your local NAPA store, fitting is 1/4 pipe- 3/8'' barb. And you are correct, these year models did not have the filter, they came on the later model trucks sometimes in the late 80s I believe

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

That filter is for a corvette. I may see if I can pick one up at the LKQ yard next time I'm there off of a late model truck. I wonder if there will be much difference in my brakes with the 3/8" compared to 1/4" fitting? It can't hurt I guess.:chevy:

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

My truck is a 1970. Would it use the same size fitting kwmech recommended for that spot on the back of the intake manifold?

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

I would think so but not 100% sure. I'm going today to O-Reilly's and see if I can get the fitting & filter. I will post later in the day if I get them and installed. Weather here is suppose to be rainy so it may not happen. :chevy:

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

Yes all boosters require the 3/8 hose or 11/32. My napa store has the 'booster' hose in 11/32

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

My '69 with a 350 did not have power brakes as an option. Part of the original purchase was that the dealer would add power brakes prior to delivery. The Quadrajet did not have a vacuum port on the back of the carb. Below is a picture of the vacuum fitting they used on the 4 barrel manifold. It has 3 ports since it is also the vacuum source for A/C and the transmission modulator. The original factory setup probably looked like that in Andy's pictures in post 3, and they just added an adaptor for the brakes.

Part number 302181, 302179 or 303313 in the attached Corvette Central link is what I used when I restored the truck. The link also has other fitting options with 2 or 3 ports depending on your requirements for A/C and auto transmission.

https://www.corvettecentral.com/sear...tting&count=27

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

My ‘68 also received a booster at the dealer and had the same fittings as FirstOwner69 shows. I guess that would be the “stock” look for power brakes that aren’t on the RPO list, but I’ll probably just buy that three-way intake fitting when I add AC.

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

I went to O-Reilly's and Advance auto both told me the filter isn't available right now. Don't know when it will come available. So I guess I'll see if I can find one in the Junk yard. I did get the vacuum port though but only in a straight not a ninty, like I wanted so I hope I can find both when I go to the yard later.
It's a 3/8" thread with 3/8' barb fitting. Not a 1/4" thread as in the picture. Left side is what I had.
Couldn't tell any difference in the feel of the brakes though.:chevy:

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

Yeah, I checked all over for the brake booster filter but I couldn't find anyone that had it either. My manifold also uses the 3/8" thread.

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

When junkyard shopping don’t pass by those old Ford trucks. Pop the hood and you’ll find a greater variety of those vacuum fittings. Many multi-port styles.

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

I found everything on line but I don't want to order from different places. The Camaro places have the filter but they all show 1/2" threads on the vacuum port.
I did find the 3/8" straight port and installed with hose but don't like it cause it makes the hose ride under the air housing rubbing on it.:chevy:

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

Hey Andy,

is this the type of fitting you were looking for?

https://www.ebay.com/itm/INTAKE-MANI...oAAOSwKEtdJ1Gg

I'm not familiar with these fittings but I found the same on you found at Oreilly. Why does the Oreilly one cause the air housing rubbing but the 90 degree one would not? The barbs both stick out on the side. The only difference I see is the square head on one and a hex head on the other. I'm just trying to learn here.

Thanks

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

Yes that's what I want. The straight port makes the hose go straight up and it's under the air breather housing so it is rubbing the housing and could rub a hole in the line after awhile.
The ninety head like you pictured would shoot the line straight over to the booster and shorten the hose up also. I took the new gas cap I bought back and while there I looked and O-R does have the 3/8" ninety but it's a Elderbrock part that is $28.99! Not worth that much when a brass will do the same job for way less $$$$$.
Lowes are H-D should have it I hope.:chevy:

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

OK, I ordered 2 NOS GM brake line booster filters for $16.00 each. They have a built in 90 so I plan to just use them and not worry about the dang fitting.:chevy:

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

I read that the filters are supposed to be changed once a year. It was on a Corvette or Z28 forum I believe. If that’s true, it’d be nice if they were readily available.

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

Yea but like most things they are not. I doubt I change them every year though any way. I wait until they clog up good then change them! :lol::lol:


It's still better than not having one I guess!:chevy::lol::lol::lol:

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

IIRC those booster filters were introduced when egr manifolds were used. Normal non egr intake wouldn’t have any excess exhaust fumes to worry about.

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

:lol::lol::lol::lol::lol:

Now you comment after I ordered 2 of them! Well I guess I can use them for insurance on the ramp truck.
:chevy:

Re: Need to Know Factory Vacuum Hose Setup For My Delco Brake Booster
 

Never heard of that EVER. Never seen it in any service manuals or owners manuals. EGR valves came out in the 70s and I never saw the filters until the 90s