rebuilding a fuel pump

[perry113]

Hi.
Is there anyone out there who rebuilds the early style pumps on a 230SL? Or is does anyone sell a complete fuel pump rebuild kit.
Thanks in advance.
Peter

[twistedtree]

Yes, I just had 2 rebuilt by H&R fuel injection on Long Island.  They look like new, and it cost under $300 each.  (631) 589-1600

[wwheeler]

I had my early stlye W111 pump rebuilt. It didn't for long the first time, sent it back and it quit again. I ended up just buying a new style.

Mine was whining with an erratic pitch and finally stopped. Maybe if I had rebuilt it sooner, the rebuild would have turned out better.

[twistedtree]

Where did you have it rebuilt?  H&R?  I sure hope mine last.

[George Des]

There are many posts on the rebuidling of the large style pump and there is also an extensive article in the Tech Manual. The success of the rebuild is largely dependent upon the condition of the pump and what parts are actually replaced. Normally a rebuild will includea thorough cleaning, all new bearings, rubber and copper seals, new brushes, new screws nuts and washers, a new woodruff key and tab washer if required. The main bellows seals are no longer available so this part is typically re-used. If it has a hole in it, you usually have to find another usable one from a donor pump. The armature is also usually re-usable, but if the commutator is worn too much it is best to have it re-wound with a new comm. Rebuild kits are not available from MB but in the past, I have made up some kits with aftermarket parts and these have been successfully used by some of the members on this site to rebuild their own pumps. I'll let them chime in on how this worked or did not work for them. Hope this helps.

George

[wwheeler]

H&R did rebuild mine but I don't fault them. Like I said, I should have sent it in much earlier. It was in bad shape. I just didn't know at that point (just had the car a few months) what a healthy pump should sound like.

I treasure originality, but that is one part that is just to important to me to mess around with given it's less than 100% successful rebuild history. Once it stops, you stop! Tow truck anyone?

[George Des]

H&R rebuilt my fuel injector pump and did a fantastic job. I've never had them do a feed pump rebuild--I do my own--so I can not comment on how they do on those. I can tell you from my own experience rebuilding many, many of these, that  the pumps should be gone through completely with all the wear parts replaced, such as the bearings, seals, brushes, tab washer with snap ring, woodruff key etc.  Parts replacement should also include a rewound armature with a replacement commutator if it is deeply scored or worn down. If not rewound, it should be replaced with a donor armature that is in better shape.  In order to avoid any leakage, it is critical that the bellows seal be in good shape, properly stretched to put pressure on its mating surface in the pump housing and the small o-ring at the top of the seal properly sized in order to seal the top of the bellows-new bellows seals are NLA. If a rebuild is done in this way, there is every reason to expect the pump will perform satisfactorily for a very long time.

George

[County Guy]

Hi.  Thanks for all the advice on this topic.  I worked on the pump that came with my car a year ago.  It was pretty badly worn and though I got it running just 'OK', I bought another on-line that worked better.  I tested them both as described in the Tech Manual before putting them away for the winter.  You can probably anticipate what I'm going to say now.  Yes, the fuel dried up and both pumps froze up.  (There's a lesson to be learned here.)  I've tried freeing them up with penetrating oil and air pressure but it doesn't work.  I've opened up the one I bought as a replacement and based on what I see, would like to give it to someone to rebuild.  I can't find anyone in my area (Toronto) and wonder if anyone there has a solution to this problem.  I've read about H&R in Bohemia but thought there might be someone on this side of the border.  I would appreciate any advice you might have. 

Thanks, Lockie