The Stovebolt Site Forums The Shop Area General Truck Talk Fuel Pump Gasket Material

When I pulled off my fuel pump, the gasket broke with half staying on the pump and a ragged half stuck to the block.

Can I use RTV gasket material (black or blue Permatex brand) instead of a paper gasket? I doubt I can find a suitable gasket at a FLAPS in the area and am impatient to order/wait for such a small dollar item.

While I'm at it, why is the one fuel pump bolt hollow? What purpose does this serve?

Thanks.

Bill

Bill,

If you are referring to a standard fuel pump on a 1958 235 truck engine, you must have at least one NAPA in the Fort Worth area that has part number: FEL-PRO Gaskets: FPG 6579, Price: $1.49

It will be interesting to read the responses regarding the bolt.

Take a picture of the hole bolt you are asking about please.

It serves to replace the one that they dropped in the mud along side the road when the were putting the pump in the last time. It was the only one that they could find rolling around under the seat.
Take Tim's advice and do it right the first time or you will just be doing it again later.
DG

Nope, I don't buy it Denny. The shop manual specifically says that the right bolt is the hollow one. This is a factory item.

Tim, you blew me away with that info. I just pictured the response I expected if I went in asking for it by application. WAY bad assumption on my part. I'll be there tomorrow to get it by part number. I can't thank you enough.

Funny summary of my fuel line replacement adventure:
FLAP #1 - they only had ONE 5/16" line.
FLAP #2 - I could borrow their tubing bender, but they had NO lines
FLAP #3 - ONE (spare) 5/16" line and ONE3/16" line for the vacuum line under the carb. I ended up returning it because it was metric.
FLAP #4 - TWO 3/16" lines.

I'll go BACK to numbers 2 (bender return,) 3 (spare line return,) and 4 (gasket) tomorrow.

Bill

Bill - I can't recall ever seeing a hollow bolt on a 235 fuel pump mount, nor find it referenced in either my 57 manual or the online 55 manual .... elaborate please

Bill

Same here, in exactly what manual were your looking? I’ve got a 1946-72 ½ thru 1 ton truck, series 10-20-30 GM Parts Catalog and I looked in groups 3.900 thru 3.935 and didn’t see any cap screw with a hole in it mentioned. Also looked in the 1955 and 1959-60 shop manuals and again, no mention of a hollow bolt or with a hole in it.

DG

I thought, when I got to that "weird bolt", it was something the PO did. When I consulted my ('58) shop manual, I found these references:

Page 10-36, under Fuel Pump Removal, 6 and 8-Cylinder Pumps:
1. Disconnect fuel inlet and outlet pipes at fuel pump fuel cover and vacuum line and cross-over hose is disconnected at hollow bolt on right side of pump on 6 cylinder models. (No typo there- I wrote it exactly as written in the manual.)
2. Remove two fuel pump mounting bolts and lockwashers and ...

Page 10-39, under Fuel Pump Installation, 6 Cylinder Pump it reads:
1. Install fuel pump gasket and fuel pump.
2. Install fuel pump mounting bolts and lock washers.
NOTE: Right hand bolt is hollow.
3. Connect fuel and vacuum hose and hose to hollow bolt on pump assembly. (No typo there- I typed it exactly as it is written.)
4. Connect vacuum hose to check valve assembly if removed.

Beats me where this "check valve assembly" is. It does not show up in either the (fig 54, pg 10-34) 6 cylinder diagram or the (fig 55, pg 10-34) 8 cylinder diagram.

I had nothing connected to the hollow bolt. I have two vacuum hoses coming out of the lower end of the pump. One barb has a hose to routes back to the rear of the engine. (I can't recall where it ends.) The other hose was loose. I assume this hose connects to the hollow bolt.

Incidentally, my hollow bolt wasn't so hollow: it was jam-packed full of gunk. I cleared it out with some bailing wire.

The 8 cylinder instructions to install the pump make no reference to a hollow bolt.

The manual is 1958 Chevrolet Truck Shop Manual, with "RS-63-S&M" on the bottom left corner of the cover.

Thoughts?

Bill

None of my other '55-'59 manuals make any mention of a hollow bolt, only the '58, and it's somewhat cryptic about it. From what I can tell, it has to do with the vacuum pump, but I can't really figure why they would want the vacuum pump to be connected into the crankcase like that.
BTW, the other end of the vacuum hose should go to the windsheild wiper switch.

huh ... I thought pumps with vacuum fittings were for wiper boost [one line to manifold below carb, one to wiper thru firewall], be odd to have anything from that hooked into the crankcase, although it wouldn't be suprising to have a check valve on anything that did - might have something to do with a PVC mod for 58? I'd see if the 'loose' hose was sucking or blowing, if it's not capped off ... and do you have vacuum wipers?

Bill

Well that's certainly an new one on me, but it still doesn't make any sense. Wish I had that shop manual and I'd also like to see some pictures of this pump and bolt and the plumbing.

DG

just guessing here, but could it be oil supply to the fuel pump for lubrication?

Bill/Longbox55 - I'm glad you confirmed seeing it in the manual. I know what I'm seeing, but it confirms I'm not misreading it!

Denny - I'll make a scan of the pages that reference it, but I didn't see anything besides text- no diagram, no photo, etc. I'll take a photo of the pump and the bolt.

Bill/Squeeze - Yup, I have vacuum wipers. Works well too, after I lubed the paddle!



My truck runs really well. I don't think I have a vacuum leak. I hooked it up to an old school "engine analyzer", a Craftsman unit that my dad had since the mid-70s that has a meter on it and helps you set idle rpm, dwell, etc. I've got the engine dialed-in even with the one hose connected to nothing. It runs like a sewing machine. My project, changing out the fuel line and the vacuum line at the distributor, was all about looks. I was tired of seeing kinked-up rusty lines snaking around the bay so I bought new ones and made them fit precisely. (Looks great, BTW!) When I started the engine ran well, but until I get the gasket and get it all back together, I can't make any statement about how it runs after replacing the lines.


Here are my vacuum routings:

A - One hose under the fuel pump connects to a rigid line, then runs toward the rear of the block. This is the one that I'm not sure where it ultimately leads. No guarantees on the "appropriateness" of this routing. It could be PO-influenced.

B - The second hose under the fuel pump routed to nowhere- it just hung. It had some grime in it but it wasn't plugged. I will connect this to the hollow bolt once I get the pump gasket, hopefully today. Like Bill/Squeeze implied- the crankcase isn't vacuum tight so pulling from the block will probably be not much different from pulling from atmosphere.

C - I have a rigid vacuum line that routes from the distributor to the carburetor.

D - I have a vacuum hose from the carburetor base that runs inside the cab and is the vacuum supply to the wiper motor.


It's funny that this thread started with gasket material and really ended up being about this confounded bolt!

Thanks for weighing-in, guys. I really appreciate getting the benefit of your thoughts. It is as if I have the A-Team looking over my shoulder.

Bill (#3)

http://good-times.webshots.com/photo/2180603440101570251FXBOzG

pic of vacuum/fuel pump...

http://good-times.webshots.com/photo/2911556190101570251bjwsJD

Vacuum lines to carb....

http://good-times.webshots.com/photo/2443265400101570251XzlaeF

Vacuum line to firewall....hose connects to vacuum wipers...

RPO-340 in the back of the assembly manual shows the layout for the lines on the fuel/vacuum pump, looks like yours, although there's nothing there I see about the hollow bolt one of lifes little mysteries

Bill

1958GMCNut - I have only one vacuum line routed from the passenger side of the engine to the carb. It routes from the distributor directly to the carb casting. Unlike you, I have one 3/16" line (carb vacuum supply) and one 5/16" line (carb fuel supply) routed around the valve cover.

The vacuum line from the fuel pump that I couldn't recall where it went ended up going inside of the cab, just inboard of the heater connections at the heater control valve.

Follow-Up:
NAPA had the gasket that Tim referred me to. (Thanks!) I got everything back together and she purrs like a kitten. The new lines look fantastic. My next project will be to replace the fuel line between the tank and the pump and to replace the rusty rigid line between the vacuum hose from the fuel pump and the cab penetration. Compared to this weekend's project, these should be much more forgiving.

Bill

The Vacuum pump is an assist for the wipers....
routing is intake manifold to vaccum assist pump then to vacuum wiper motor....

I think the engine in the Canadian truck is either a 235 or 261, not a US GMC engine.

Did you ever solve the hollow bolt mystery?

I and plenty of other guys used to just make one as needed using the usual Cover of a Spiral Bound Notebook.

I'd saturate it in Oil and mount to clean surfaces.

None ever failed that I know of.

There is no strain or pressure for this condition. So, any thin pasteboard would work fine, long as the mating surfaces are clean and flat.

To answer the original question, the RTV would have worked fine. But I like the old idea of cutting one out of paper. There are plenty of gaskets out there made from "fish paper" or "cellulosic" material. For other applications I have cut gaskets from thin aluminum stock, and even made a head gasket for my bike from a large copper pipe split, flattened, cut and heat treated.

...same as the notebook cover. I have used a saltine cracker box many times for many different gaskets.

I have used what was left over from the nails coming through the cut out cornflake box sole of the two dollar shoe don't fit my foot. Wrote a song about it, maybe I'll sing it for y'all one day.
Carl

Carl, I would say something but we want to keep this on topic