r107 1971 heater box removal

[Isdyldan]

Hi all,
Please could someone advise me - I'm trying to remove the wiper linkage on my project r107 350SL because it's seized and there is rust in the bulkhead that I need to repair. I've got the dash out and now trying to remove the heater box. I've undone all the fixing which I read in this guide:
http://mercedesdiy.blogspot.com/2018/02/450sl-heater-box-mystery.html
but it still seems quite solidly fixed in place. I haven't removed the blower motor as I could accessed the hose clamps through the scuttle grills - do I need to remove the motor to release the heater box please?
Thanks, Dylan

 

[star]

I’m pretty sure you do and heater the heater pipes.

 

[Isdyldan]

Thanks. Blower motor out and I can see I have a few repairs to do! Heater box still not moving much. Maybe I need to be more aggressive with it.

 

[Isdyldan]

Hi - I just thought I'd update the progress here - partly so I've got a record to refer back to, and maybe it will help someone else. I removed the heater blower, but it doesn't actually need to come out unless it gives you better access to the heater hose clamps. I actually ended up cutting the hoses off as they were very old and perished, and would have been very hard to get off the heater box pipes in the tight working area. It's a good time to change those hoses anyway. I accessed the hoses through the scuttle grills, but they were a sod to remove because somewhere down the line the windscreen had been replaced and the black mastic was gripping the ends of the grills. It was also strongly gripping the lower windscreen chrome trim which I have wrecked removing it. I'm not sure yet if it will be ok to reuse - they are expensive.
Anyway, with the hoses removed, I found a few more fixings - ones from the slider controls to the main brace (as well as the slider control support frame fixings). The heater box it a lot closer to coming out, but not quite. I have just read the bit about bending the heater box pipes so I'll do that this weekend. There is some corrosion, but from what I've seen so far, I think I've got away with needing a complete bulkhead repair section. Time will tell though.... Here's a few photo's if anyone is interested.

 

[LostKiwi]

Well done. I think you're lucky to have caught that. The bulkhead on those is notorious for rusting through giving damp interiors and it can be very expensive to fix.

 

[Isdyldan]

So, I've got the wiper linkage out and am currently unseizing it in a vice with lots of wd40. I thought I may as well add the following info as I struggled to find it elsewhere, so may be useful to someone. It's not actually related to heater box so maybe it should bb moved?
Now the wiper linkage was out, I thought I've test the motor, but struggled to find an info on how to test it. i applied 12V to random pins bat with nothing happening apart from a few relay clicks I decided to remove it. Still nothing happening by applying 12V, so I took it apart.

It was in quite a mess but essentially it was ok so I got as much rust off the rotor as possible and could see that the carbon brush little springs were fine, but the carbon contacts were stuck. WD40 again!

Assembly was a bit tricky as you need to hold the rotor in place (maybe it's called the armature?) between the carbon brushes as you slide the magnetic body back over it - it wants to jump into the body due to the magnets and then the carbon contact are it the wrong place stopping the body sliding on. If you take the back cover off exposing the large cog that turns the wiper shaft, it is possible to clamp this with a g-clamp to stop it turning. This then stops the armature being pulled back out of the brushes when you put the magnetic cover back on.
The last bit is to push the two little square locking nuts back into the sides to fighting it all up - be careful though as these little nuts get 'sucked' inside by the magnet and you have to take it all apart again!

To test it, there are two wires actually going into the motor - a red and a green. These are the 12V supplies to the motor for slow and fast speeds, so you can test at this stage by grounding the metal motor body and applying 12V in turn to these two wires.

With it all back together, testing at the plug pins on the motor can be done using the last diagram. Hope this is helpful to someone!

 

[Isdyldan]

Hi all, well it's all back together and seems to work, but the wipers don't park. It's not that they don't park in the right place - they don't seem to park properly at all - they just stop dead when you turn them off. Is there a separate circuit for the parking please?

 

[RaceDiagnostics]

Self parking is normally handled withing the wiper motor itself, is there a chance you left something out.

 

[LostKiwi]

Hi all, well it's all back together and seems to work, but the wipers don't park. It's not that they don't park in the right place - they don't seem to park properly at all - they just stop dead when you turn them off. Is there a separate circuit for the parking please?

If you look at your first window you can see the parking switch.

This needs looking at as it's not operating to break the circuit.

 

[Isdyldan]

Thanks - I’ll take it apart again and look.
The blower motor was knackered too but this one is beyond repair. I’ve ordered a new motor.
Dylan