repair advice for 752 UP streamliner

Have you cleaned the commutator surface and checked the brushes? The brushes might be worn out. That can weaken the motor. If the motor has been sitting for a long time, you might want to bench run it for a while to get the fresh oil and gear lube to work into the nooks  and crannies. Check afterwards, it might need a little more lube.

Check with Hennings Trains for a replacement pick up. You can search and find a new one online. Check for videos on how to replace it. Supposedly, the frame can be gently pryed slightly apart to change the pick up.

It looks like a nice unit.

Good luck!

Don't fill the grooves with solder, but you might try making a U shaped cover out of hobby sheet brass or copper, and soldering that over the worn contact.  I have tried springing the frame of a 1688 to open it up get a new contact in with no luck, maybe I don't have the knack but it sure seemed like it would take a lot of force to spread the sides.  The only place I have succeeded with that, is opening an E unit to replace contacts and drum.

Thanks to all who provided suggestions.  Here's an update...

I added solder to the pickups and they no longer catch on curves - as Red Green says "this is only temporary unless it works".  I'm going to check on new pickups with Train Tender or Henning's, but for the time being it is working well.  Also ground off a bit of the motor frame at the rear where it was bumping into the frame - about 1/8" allows a lot of additional movement.  Shaved off a bit of the fiber insulator near the pilot to allow more clearance - there's still plenty of meat to keep the wheels from hitting the frame.  It's also possible that removing and reinstalling the motor allowed it to re-seat the mounting ball.  After all that, it stays on O72 curves and usually makes it through the switches.  After lubing and running the motor, it functions a lot better.

The whistle doesn't work and is probably toast.  But considering that I paid only $225 for the set, I'm happy - worst case scenario is that it will make a great display piece.

Thanks to all who provided suggestions.

The whistle can be serviced also. It is probably really dry. If it doesn't engage, then the relay might need something. As long as the relay is good, you can clean and lube it, it should work again.

Search for Lionel 752M-23 if you’re interested in finding a replacement sliding contact pickup shoe assembly.

When trying to replace a collector assembly, you must first loosen the wheels on the motor.  The tool you need to replace the collector is a common "E" clip pliers. It has two tits to engage an "E" ring part. You must reverse the handle so that when you squeeze it, itopens the tit jaws. With the wheels spread about an 1/8" you can now engage the tits of the tool inside the motor frame, squeeze gently and lift out the collector.  Harry