zaklee_in_MS

I have a '98 E300DT. I had a lot of noise from the front D/S. I took it in for a A/C check and they said that a bolt was loose. The tightened it.

A month or so later I heard a lot more noise in the same area and noticed the compressor vibrating violently. I took it to what I think is a reputable A/C repair shop.

They investigated and then told me that there are supposed to be four bolts holding the compressor on. They went on to say that one was missing, two were loose and the last was broken off. They siad they ordered new bolts and installed them with Locktite so they shouldn't loosen up.

Couple months later now and the noise is back. I can only find two bolt locations looking down from the top. One of them is finger tight. It certainly doesn't look like a new bolt and, get this, they used a washer and an oversized nut as spacers. When I pulled it out I found the end business end had either broken off or been cut off. I think cut but very poorly. Also, there was no sign of Locktite.

I'm guessing they cut this bolt and used the spacer because they put it into the hole where the broken bolt was. By the time they cut the bolt and added the spacers, there must have been very little thread actually in use.

So what now? How should I fix this? How many bolts are there really (I'm thinking only the two)? I'm sure this SHOULD be drilled out but that's a big job and I'd rather avoid it if possible. Maybe it should just get welded on...

RichardM98

IIRC there are 4 bolts. Two that are easy, one that's difficult and one that's a bear! I also believe one bolt is shorter than the other three. I'm of the opinion that if MB engineers' thought that 4 were needed they probably are.

A shop with the right tools should be able to extract the broken bolt, clean up the threads and install new bolts from the dealer. So far it seems like you have been getting faulty repairs.

ohlord

and the solution.
http://www.emhart.com/brands/heli-coil/

zaklee_in_MS

Totally agree about faulty repairs. The shop that did the last repair used a bolt that was too long. They cut it off and used a spacer. I'm pretty sure the shortened bolt didn't have enough thread on it so when they drove it in to full depth it stripped out the first 15-20mm of threads. That's the easiest one to get to (top front) so shouldn't be too bad drilling out for heli-coil.

MB parts says they're are (4) holes but there are only (3) 8x95 bolts. If that's true, the claim of one broken off in the block is likely false. I am hopeful!

There is a fourth bolt shown in the MB parts diagram but it's short and holds a bracket/spacer between the compressor and the block. The other three appear to pass through the spacer.

Does this sound right or are you certain that there are four plus the one in the bracket? Any idea how I could verify any of this? If there are four I need to find the size of the fourth bolt and figure out which hole it goes in.

RichardM98

About a year ago I replaced my motor mounts. It's necessary to unmount the a/c compressor and slide it forward to get the left motor mount out. I seem to recall four but I don't think I would have removed the bracket if unnecessary.

I would get under the car and check. The uppermost one is hard to see from below. Also, you may need to remove the anti-noise panels.

zaklee_in_MS

I also replaced my motor mounts about 18 months ago. I followed a DIY I found here or at benzworld. Don't recall which but I know that I didn't have to take my AC compressor (or anything else) off to do it. Are we talking about he same car here?

RichardM98

Motor mount replacement varies a little depending on engine and suspension but I believe the A/C compressor is the same so the same mounting bolt pattern.

My car is a E320 wagon.

zaklee_in_MS

Gotcha. I've ordered the bolts MB can ID. Once they arrive I'm going to compare one to the bolt that hack mechanic put in. If it looks like threads were damaged I'll be taking it to a well respected indie for repair. If it looks ok, I'll get in and attempt repairs myself. Either way I'll report back to close the loop.

Appreciate your responses.

Zak

PS. The shop I went to has since fired the guy who "repaired" my car. They've also agreed to a full refund and tentatively agreed to pay for repairs to that bolt hole if necessary. At least the shop is taking responsibility.

RichardM98

Delux2d

question.. IF my AC Compresor doesnt engage, does that mean that the Compressor is bad? There is enough charge in the system. Or shoud I go about cleaning my duovalve?

illest

Run the diagnostics from elcass benz and post the results.

zaklee_in_MS

'Tis true. There are only three 8x95 bolts. Drilled out broken bolt at back and installed Heli-Coil in front upper. Car's never been quieter! The first shop covered cost to remove compressor and repair stripped threads. I paid $50 to remove broken bolt but didn't have extra expense of removing compressor.