Packard Forum Index » V-8 (1955-56)

I thot all vacuum wiper set ups had balance valves.

Believe valve was only 55-6 with sump pump. Otherwise from intake manifold, thru pump then wiper was the way other cars did. Not sure the fuel pump setup has enough to offer to trigger the valve & run wiper on its own.

Correct. You don't use a balance valve on conventional dual-action fuel pump systems because there is nothing to balance, only one vacuum feed to the wipers as the vacuum section of the fuel pump is in series between the manifold and the wiper motor. The vacuum balance valve is used (55/56 Packard, Cadillac, Buick) because you have two parallel vacuum sources.

that carter pump is the exact same one as the airtex, just a different brand. i checked them both out before i bought my pump. the airtex cost me less. but yes it will work. the second hole you see is the inlet. where on our cars it would be on the other side, ford had it on the same side as the outlet. the third hole is just a blind hole. in some apps it would be used insted of the one below it.

I never saw the vacuum pump of any two stage fuel pumps last more than 15K to 30K miles at the max.

It's a bit hazey to me but IIRC the intake manifold connects to the vacuum pump and the vacuum pump connects to the wipers. i.e. engine vacuum passes thru the PUMP before it gets to the wiper motor????? I think that's what Owen was trying to say with all of the "series" and "parallel" jargon.

THE PROBLEM is that the vacuum protion of the two stage fuel pump is constantly exposed to fuel, AIR AND MOISTURE. NOT a good mix.

Route thru a balancing valve to eleminate the short life tendency of the two stage pumps. OR any other way to keep the fuel,air and mositure out of the vacuum pump. I never actualy tried routing thru a balancing valve on any of my cars tho. Should work.

I never saw the vacuum pump of any two stage fuel pumps last more than 15K to 30K miles at the max.

I think the failure is much more the simple act of flexing a couple of million times rather than chemical attack from the outside (rubber side). Moisture and air certainly don't bother most suitable synthetic rubbers, and they are made to be compatible with gas and oil. All the ones I've looked at failed internally with the plies of fabric and rubber separating. No, they don't last forever but I think you estimate of 15-30K max is quite a bit short of the mark.

I can't say that i ever got into many of the two stage fuel/vac pumps for repair. Had several cars with them and they were used as late as the early 70's especialy on bottom of the line AMC products of which i had owned at least 6. Never had one make it over 25K miles.
I remeber one AMC/Jeep mechanic indicate that backfire thru the intake would shorten vac pump life but i really don't know. When they went bad i just lived with it at the time especialy since i lived in rather flat level michigan at the time. The AMC 2wo stage pump was about $80 back in the early to late 70's. A standard pump about $7 - $15.

The only nice Gremlin i had was a 74 Levi's Gremlin. Out of the 6ix AMC products i owned it was the only one with electric wipers. The rest were vacuum rangeing in years from 1965 - 1973. They were all very low mileage, one owner cars when i got them. Otherwise, i would not have bought them. COuldn't hardly give a nice used AMC product away back then. So they were CHEAP.

I've a bit of a soft spot for a couple of AMC products from the past, my Dad had a 1961 Ambassador wagon, AMC-327 V8, stick with OD, blackwalls with small hubcaps. Very plush inside, and real "fooler" for performance.

And the Marlin - always liked them.

hey owen, i have a marlin owner's manual on e-bay i'll sell ya! lol there were several amc products i liked. but around here it's hard to find a good one to build. i kinda grew up in one. my best friend's (bub) dad and g-pa owned an amc dealership. mom had, and "bub" has now the 74 hornet wagon we went every where in.

I had the same problem with both of my 1955 Packard Clippers. I went to Carquest and found that a Master M fuel pump #6866, which fits a Chrysler 318 early 70s, bolts right in. I drive in Phoenix, AZ elevation 1200 feet and at the north Rim of the Grand Canyon elevation 8800 feet and had no problems. You can get a cross reference at NAPA for the same part. I only paid $16.50 and it has a lifetime warranty and since I plan to keep the car a long time I hope the company is still in business when I need to replace it. I have put over 30000 miles on this fuel pump.