Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: County Guy on March 20, 2017, 03:14:35

Title: tall fuel pump commutator
Post by: County Guy on March 20, 2017, 03:14:35

Hi.  After many hours of frustration attempting to make the old 'tall' pump work, I installed a substitute.  Now, several years later, I'm tired of listening to the noise it puts out, so I am rebuilding the old one that has been sitting on the shelf.  I don't expect to encounter too much trouble as it spins when current is applied.  BUT, have a look at the photo of the commutator on the rotor.  Is it too badly worn to function properly?  I suspect that the power output will diminish if the commutator is not isolating each segment properly.  If you feel that the commutator is too badly worn, what suggestions do you have for me?  Is there someone who can replace the worn commutator?  I would appreciate any help you might give me.

Thanks, Lockie

Title: Re: tall fuel pump commutator
Post by: Tyler S on March 20, 2017, 03:41:58

Lockie, It does look pretty bad to me. See George's post. Im sure he could sell you a good used winding. See the bottom of his post.
https://www.sl113.org/forums/index.php?topic=25749.0

Title: Re: tall fuel pump commutator
Post by: ja17 on March 20, 2017, 04:59:20

It seems, that as the commutator diameter decreases, so the usable length of the brushes decreases. The brushes will also wear faster since the contact spot is smaller (against a smaller diameter commutator). With the smaller contact spot, the PSI increases on the brushes. In addition, if the commutator is not perfectly smooth, brush wear will greatly increase.

Title: Re: tall fuel pump commutator
Post by: County Guy on March 20, 2017, 16:51:46

Thank you for the replies.  I hadn't really thought about how the diminishing diameter would effect the performance.  I sensed that it would reduce the overall output power but not how that would happen.  Good point about the brush travel.  I hadn't thought of that either.

I'm going to reassemble the pump with the better commutator and wait and see what suggestions members might have before deciding what to do with the one with the worst wear. 

Has anyone ever had an electrician replace the commutator on the rotor?

Title: Re: tall fuel pump commutator
Post by: BaronYoungman on March 20, 2017, 19:22:41

If you decide you are going to go the short pump route, I have rebuilt ones available. Bob (630) 903-9877