Smog pump/pulley questions
 

1991 190E 2.6

Some pump/pulley began whirring/whining a few days ago. I've narrowed it down to the smog pump and/or smog pump pulley.

Questions:
1. What are these things made of? Gold? $1,000? Found a rebuilt pump with pulley for about $350.
2. Typically, what causes this problem? Is it the pump or is it the pulley?
2b. If pump, can't I just disconnect the electric to the pump and be done with it?
2c. If pulley, how difficult is it to install a correct sized belt that bypasses the pump considering moderate to pretty good technical skills?
3. Considering same skills, how difficult would it be for me to r/r said pump or pulley?
4. How do I confirm whether it is the pump or the pulley?

-- It seems to continue even after the engine is warm. No matter how long it has been running, if I raise the rpms it is evident.

Thanks mucho for the info.

Anyone have links to the rebuilds mentioned in other threads and would the quality be ok?

Bump to get some exposure.

As per my question regarding the replacement of smog pump -- looks fairly straightforward but I haven't replaced a belt so I'll have to learn how to loosen/tighten the belt.

I suppose my main question is how do I know if it is the pump or the pulley? If pulley, how do I change the pulley on the pump?

Any info is appreciated.

I'm not familiar with the 190, but my 85 380SE had a smog pump that was shot. I'm talking totally rusted out, with a bad clutch. As I understand it, this thing is useful during warmup only to pump air into the exhaust (not sure here) to reduce emmissions at the cat converter. It apparantly does zip after warm up. So, lucky as I am to live where emissions testing isn't yet mandatory, I removed it, belt, hoses, and all, plugging up the attached connections at the engine.

The 190 may run something else off the same belt, though, I don't know. If so, and you want to remove the pump only, run a tape over the pulleys and get a 3 belts from the parts store, 1 smaller, 1 the length of the tape, and 1 bigger. Return the 2 that you don't need.

If you'll need it for testing, it's easy to remove and inspect. If the internal vanes aren't beat, you probably have a bad clutch, which works like the A/C compressor clutch (and may be interchangeable too). If it squeels all the time, even when the clutch is 'free-wheeling', then you'll likely need to replace a bearing.

You don't say? My drivers' door lock is non-functional, too. Pass along the info.

Thanks for the info -- keep it coming.

The most common failure on the air pump is the bearing in the clutch. The rebuilt units seem to be OK to use and cost much less than a new pump. If you were to remove the pump and want to run without the pump you would need a shorter belt. The belt from the 87 and 88 year cars should fit without the pump. The part # is 008 997 47 92 and it is 2257mm long. Hope this helps, Robert.

Thanks, I appreciate the info.

If I remove the smog pump, what types of pipes, etc., do I need to close up and how should I do that?

How do I remove the 4th bolt -- the one on the bottom closest to the engine side? I can't even get to it. I have the first 3 out, but can't get this one out. I also have the recommended belt from your post -- it is 88.5 inches long vs. the standard 95.