Fuel pump Heat feeler question

[230SL]

Its not the heat feeler in general, but the peice it contacts.  Below the heat feeler is an aluminum assembly with a breather and fitting.  My question is what does the mechanism inside it do?? Mine seems frozen whereas the part that extrudes as a pin from the bottom will not go up or down and it seems to have a brass insert where the heat feeler would push against. 

-So is this a complete pin in which the feeler hit the top of the brass insert and pushes the extruding pin below which contacts something in the fuel distributor where it bolts on to? 

-Aside from that i have numerous spacers stainless circular are they used to compensate for the Altitude compensator?

Oh and for anyone asking why i would take any of this apart and not mark anything the answer is i did not, the car was disassembled by another individual and parts were in a plastic bag with screws,washers,pins all at the bottom of the bag and using books and the help of 113 enthusiats such as the readers i have been able to little by little build the car back up.

[ja17]

Hello,

Yes, the mechanism below the heat feeler should be free to move. You will fill some resistance when you push down on it. If it is frozen stuck, it must be feed up. The shims below are for adjusment when new. You should be able to rmove the section with the mechanism and clean it and get it to work again.

[230SL]

Great well i got that loose and just have to find some softscrub and put it on a drill to clean the bore.  But in regards to the circular stainless steel shims those are infact part of the altitude compensator which is located to the left of the heat feeler mounted on the pump? 

I know the aluminum part which the heat feeler sits on has shims in between the aluminum and fuel distributor but these are egg shaped allowing the 2 screws to enter on each end and a circle in the middle.

[Anfinn]

I too have struggled with a non-functioning WRD. I have had it apart, lubricated it and it is smooth and free.
The heat feeler in the top I have tested in a cup of hot water, and it extends normally as far as I can tell.
Still the air was not shut off as the engine got warm.
To-day as I was going to take it off again, I looked into the lower water tube, and stuffed in there was a metal plug!
The sensor hasn't had water circulating!
So although I am happy to have found a likely cause of the problem, I am mystified why anyone should do this. Any theories??

[ja17]

Hello Anfinn
Thats a good one!
Sounds like someone thought they were plugging an interior heater line.

[jeffc280sl]

Anfinn,

Your engine may run a little cooler with the plug removed.

[230SL]

Did you ever have to move the screw which seems to limit the travel of the piston?? Mine broke oddly enough wasen't trying to unscrew it (which its not really screwed in, in the first place) just fell and hit the floor and broke the bolt head with the spring attached any way of fixing???

[ja17]

Hello,

Just replace it.  I think a pin holds it in place. I think the same screw was used on the more common two piston pump on sedans of the era.