Rebuilding the distributor - tips please!

[Cees Klumper]

Recently I got a Bosch rebuild set for my distributor from Dan Caron. I thought his would contain maybe 10 different parts, but I was wrong: it's more like 70!

Has anyone here gone through the process, and can you give me some do's and dont's etc?

1969 280 SL automatic

[Naj ✝︎]

Hi, Cees,
I'll kick off and others can add...
Assume distributor is off the car ( if not, turn engine to timing mark for cylinder #1 to fire.i.e cam lobes for #1 at 'ten to two' position. Rotor should line up with mark on distributor rim. Reinstall in same position to start engine to reset timing with strobe)
Start from the top. Remove the condenser, cap clips, points,(or electronic system rotor/sensor), connection bolt and vacuum unit (Two screws on body and one holding bracket with pin on inside plate). If you had the correct vacuum advance when timing, ensure not to disturb the length of the rod on the vac unit. This will allow you to take out the fixed base plate together with the rotating advance plate.The rotating plate can now be separated by removing the cupped spring and ball (keep safe). Keep notes on the shims/fibre washers that come out.
Disengage the advance springs from the bottom shaft and you should be able to lift out the camshaft. Note the relationship of the cam shaft to drive shaft.
To remove the main drive shaft, first mark the position of the two tanged driver to the drive shaft (maybe centre punch both drive and shaft - these are very hard material and not easy to mark). Remove the spring wound round the middle of the driver to expose the pin. Knock this pin out with a 5mm drift. This will allow you to pull out the main shaft. Again more shims and fibre washers to take care of!! The weights/springs can now come off - held in place by very fine lock springs. Again note the washers that go below the weights.You can now check the wear on the shaft and condition of the bushes in the distributor housing. If the bushes are worn, they will have to be pulled out and new ones pushed in. May need the help of a shop here as the bushes may have to be reamed after. You can clean up the body and spray paint it after masking the Bosch tag. Turns out looking good as new!!
My 280sl came with an '048' distributor (vacuum advance - out of a 280S) so I bought a second hand '051' to rebuild. While it was very rusty on the outside, there was hardly any wear on the shafts and plates.

You will not need all the parts that came in the kit. Just shim it up to have minimum end play but still turn very easily by hand.

Assembly is in reverse order.

I'm sure some details will be missing!
naj

naj
'Kloines Scheisserle'
65 230SL
68 280SL

[dwilli3038]

Cees,

I just finished this job. It was quite difficult for me. I have two suggestions for you. Take LOTS of pictures as you take it apart (I did not) Keep Dan's E-mail address handy (I did). Actuly like anything else you just need to be careful and take your time. As you disassemble put the various old parts in order so that you know in which order to put the new ones in.



Daryl
'64 230 SL

[Cees Klumper]

Thanks for the tips guys. I performed the job Sunday night and fortunately indeed, took lots of digital photos. It was not too difficult, but you do have to note where all the washers go and in what order etc. Fortunately the copper/bronze bushings are in very good shape, so I don't have to have any work done outside. The only thing I still have to get is some good grease (I suppose white lithium grease or such will do fine) to coat the various inner parts with, before I re-assemble it all. I will be left with many extra washers etc, but I suppose Bosch figures it's more efficient to provide a "one-size-fits-all" rebuild kit, rather than stocking umpty different sets for each version of distibutor they made. I will post some "before and after" pics when I get it all done. Sure is very rewarding to be able to do this job and see the results!

[Cees Klumper]

The job is just about done, I just have to fit in my electronic ignition pick-up (instead of points), and refinish the vacuum assembly, and it will be like-new again. I was able to remove the play in the shaft with some extra shimmies, and the shaft still turns very easily. At an autoparts store I got some special-purpose Bosch distributor grease, very sticky yet slippery stuff, for about $5 - this tube should be enough for +/- 100 distributors! I guess the final test will be when the distributor is on the ("Made in Ohio") engine and I can check whether the advance/retard etc functions properly.
I found out today at the same autoparts store that a replacement (not original) Bosch distributor costs around $600. Still, some say these don't work as well as the original type. So it's worthwile to hold onto your original distributors and either rebuild them, or have them rebuilt.

[Naj ✝︎]

Cees,
I think you will find that the sticky grease(brown)is meant to be used on the pad for the pionts and may be too sticky to use between the fixed and moving advance plates and also for the weights. I prefer to use the 'blue' softer grease also made by Bosch.


naj
'Kloines Scheisserle'
65 230SL
68 280SL