Need some part numbers American Bosch:

[Rob]

Does anyone have a book with AMBAC part numbers? I have a leaking overflow valve on one of my 8VBB series pumps which allows fuel drainback. This valve also serves as a fuel check valve. If I don't start the truck at least every other day, I have to manually prime the system again with an external pump as there is no manual primer. It was going about a week for the last year or so but has regressed further. I think this effin "bio-diesel" garbage has done it in.  The transfer pump still makes and carries good fuel gallery pressure when the engine runs, but if I have manually primed it, there is a delay  before the engine runs smooth until the air purges through the system.

[kscarbel2]

Look at the 313GC fuel pump assembly breakdown at your Mack brand distributor.

[Rob]

I'll get onto that in the morning. I usually have to get them to go into some other database as the trucks are old and they readily get back to me. Lot of times I am able to get part numbers and it saves some time. I checked with the fuel shop I've used several times in the past and they don't have anything on the V8 series pumps.

Thanks,

 

[HarryS]

14 hours ago, Rob said:

Does anyone have a book with AMBAC part numbers? I have a leaking overflow valve on one of my 8VBB series pumps which allows fuel drainback. This valve also serves as a fuel check valve. If I don't start the truck at least every other day, I have to manually prime the system again with an external pump as there is no manual primer. It was going about a week for the last year or so but has regressed further. I think this effin "bio-diesel" garbage has done it in.  The transfer pump still makes and carries good fuel gallery pressure when the engine runs, but if I have manually primed it, there is a delay  before the engine runs smooth until the air purges through the system.

Rob, That sounds like the same problem I am having with '60 B, 673. It used to start right up even after long periods of not running. Now you have to crank and crank and let it stumble a few times before it smooths out. Starting for the rest of the day is fine and it runs fine. Two questions , is that check valve readily available and can it be installed with the pump on the engine? Thanks.

[Rob]

Very easy to change or rebuild on the six cylinder engine. It is the brass part on the side at the rear of the pump with the fuel hose connected. Take it off and apart, clean it up or replace anything that is worn and put it back together. That valve regulates gallery pressure inside the pump and bleeds excess back to tank. It's called a regulator on the sixes, and overflow on the V8's but does the same thing.

[Rob]

Got some part numbers and seeing if they are still available through Mack. If not I have a couple other options but that may take some time.... I could install an external check valve but would rather have the repair correct. I've recently strung all new fuel lines on the truck and don't want to remove them again.

[Rob]

Valve was researched, found and ordered. No lead time but should be a couple of weeks.

Thanks for the help.

Rob

[HarryS]

10 hours ago, Rob said:

Very easy to change or rebuild on the six cylinder engine. It is the brass part on the side at the rear of the pump with the fuel hose connected. Take it off and apart, clean it up or replace anything that is worn and put it back together. That valve regulates gallery pressure inside the pump and bleeds excess back to tank. It's called a regulator on the sixes, and overflow on the V8's but does the same thing.

Thanks for the info Rob. Good luck with yours.

[Rob]

50 minutes ago, HarryS said:

Thanks for the info Rob. Good luck with yours.

Thanks. I have an extra pump which does not have the valve installed; hence the reason I went with a replacment rather than rebuild. A rebuild set could not be located but it's probably standard parts internally and when I have the replacement, I'll take the original apart to see what's inside. Hopefully get both pumps serviceable.