Fuel Pump Surgery.........am I crazy ?? - PeachParts Mercedes-Benz Forum

David Speed · #1 10-16-2003, 07:44 AM

Low mileage fuel pump on '78 280CE...............seized with crud / varnish.........long story, but should have cleaned tank & screen as first item when getting her restarted after 5yrs

Tried 'dead blow' hammer, carby cleaner, alternating 12 volt supply.........everything short of throwing it against a brick wall

I feel it is still electrically ok, as it gives a small 'thunk' when power applied

Have cut open an old pump, so I know where the seals are and how it comes apart

The pressed crimped closure is the biggest hurdle........figured I would make several cuts to short of the seal with a Dremel........peel the flaps back carefully....and hopefully pull the top off without damaging the seal or brushes

Once the top is off...... rotating the armature back & forth by hand should free the pump without pulling it any further to pieces

Should go back together ok......and thought I could close the crimp rim with a clamp (or cable tie at a pinch)

Has anyone else operated on a Fuel Pump ?

Am I crazy to even try ?

Any advice appreciated

csnow · #2 10-16-2003, 12:06 PM

I admire your tenacity.
I generally consider the warning "No user servicable parts inside" to be a dare that simply must be tested.

But, I would not attempt this one...

For one thing, Dremel makes sparks, which could be bad.

I do not know enough about the internals to say it can't be done, but I would also imagine the seals are very tricky.

Best of luck.

G-Benz · #3 10-16-2003, 01:09 PM

Quote:

Originally posted by tkamiya
I wouldn't try it either.... It'll be difficult to seal it correctly and reliably after the repair. If the leak ocurrs, it's flamable liquid that would leak. AND it's not that expensive to buy new.

I saw a cut-out diagram somewhere.... If I'm not mistaken, its an electrical motor immersed in gasoline, isn't it?

YIKES!

The part about "not being expensive to buy new"...that's where my "cost vs. labor" decision comes into play...now if we were talking about the throttle body actuator, well yeah, I'd crack it open if I could.

Of course, we've had members resolder OVPs and they go inexpensively new as well...

David Speed · #4 10-16-2003, 10:47 PM

Quote from MB Brisbane, Australia -$669 Aussie dollars!! (~$US460) .........more than alot of people earn in a week in Oz...............not what I would call inexpensive

Will research some other sources........may even have to consider ordering from US.......If I could get it for $200 in Oz I wouldn't consider opening it up

I'm quite certain no gas left in pump........may be a little carby cleaner............should have all evaporated......so would expect fire/explosion risk to be minimal with the Dremel

My main concern would be the resealing - if it comes apart without damage.

Seems the 'Crazy' vote is winning

Still keen to hear if anyone else has repaired a Fuel Pump

AF300E · #5 10-17-2003, 02:31 AM

Give it a go!
I used to work for a benz dealership and got 2 new ones for my w124 for a decent price (i'm in melbourne by the way) but i was prepared to take them apart first. I did uncrimp one and tried for about five minutes to free the motor inside, but that was all (it wouldn't come out by the way). I would still give it a go.

haasman · #6 10-17-2003, 02:48 AM

I say try it. Just take appropriate precautions.

If you screw it up, you'll have to buy a pump anyway. If you discover something, then you'll be ahead.

Sealing the pump afterwards would also be my concern.

Do these pumps have a core value? If so, some way, some how, they are taken apart and rebuilt.

Speaking of that, possbily you could locate a rebult one that might keep the cost down.

Keep us posted,

Haasman

william rogers · #7 10-17-2003, 03:13 AM

I did it on my long gone 86 Toyoto motorhomes pump as the motorhome had not been started in over a year and the pump was frozen. I pried the crimp, pulled out the inards cleaned the varnish with carb cleaner reassembled it ,tapped the crimp back with a jewelers hammer and then sealed the crimped end with JB weld.It worked fine after that.
The funny part of the whole operation was that I cut a hole in the floor to access the plate on top of the gas tank to pull the in tank pump out as dropping the tank looked to be a very hard job.......
William Rogers.......

neileg · #8 10-17-2003, 05:12 AM

A new Bosch pump from a Bosch agent is about 100GBP in the UK.

csnow · #9 10-17-2003, 09:45 AM

They run like $160-200 here.
You would probably come out ahead even after shipping.
Some suppliers list a Pierburg pump for a few dollars less.

That pump outwardly looks exactly like the one in my 300E.
I got a 'made in Taiwan' replacement for $140 because I desperately needed it on a Sunday.

Works, but is much louder than the Bosch. Also had different diameter, so took a bit to get it mounted securely. In the end, I used closed-cell foam pipe insulation, which worked great.

Anyways, 'made in Taiwan' stuff must be cheap down there...

autozen · #10 10-17-2003, 11:04 AM

David,
What is the Bosch # on the pump? I may have a good used one in my bucket of pumps I took from cars I have scrapped out. If I have one, I'll give it to you if you pay shipping.

Peter

neileg · #11 10-17-2003, 11:45 AM

Quote:

They run like $160-200 here.

That ties up with my UK price.

David, I think you need to double check the prices. Remember, a Bosch fuel pump in a Mercedes box is the same part as a Bosch pump in a Bosch box.

David Speed · #12 10-21-2003, 03:12 AM

Thanks to all who replied

Autozen, thank you very much for your generous offer

Spent half a day on the phone and found an Importer who sold me a new Bosch pump for $A180 plus tax..........that is ~$US120........incredible price compared to MB (Aust) price of$A669 for the exact same pump!!!!

I find this unbelievable........I hope MB USA is a bit kinder to its owners with its pricing

At least some good has come out of the pump seizure.........I have found a good cheap source of the 'higher volume' service parts in Australia

David

#13 10-21-2003, 09:27 AM

David - If you want to try and salvage the old pump here is what I suggest. I had a similar pump on our 1980 Porsche 928 and because the car sat so long (6 years) it did the same thing - just a "thunk" when you applied 12 volts to it. A mechanic friend of mine told me to try the following before I bought a new one. Get a container about 3" round and about 9" high and take your old pump and remove the fittings on both ends and put it into the container. Fill the container with any good concentrated fuel system (or injector) cleaner so that it covers the pump entirely. Let the pump sit in it for 2 weeks - occasionally moving the pump up and down to force the cleaner into the pump and out. At the end of 2 weeks - take the pump out and dry it on the outside ( leave the cleaner in it) and take a 12volt supply and keep touching it to the terminals (you will get the familiar "thunk" each time) After about the 5th time - mine broke free and started pumping again. Two years later it still runs. I wire wheeled the outside of the pump and sprayed it with a clear coat and she looks good.

AF300E · #14 10-21-2003, 06:19 PM

David, if you dont mind my asking, who is the supplier you have found?

David Speed · #15 10-22-2003, 02:25 PM

Andrew........happy to supply details

Import Advantage
36 Webster Rd
Stafford
Brisbane Q4053
(07)3356 9644
1800 777 612
Fax (07)3356 9219

I understand they have recently been taken over by a Melbourne Company.....I hope that doesn't mean the end of their cheap prices.........latest invoice has Imparts Automotive Pty Ltd on it

Do you have any Australian contacts for MB parts?

David