17 hours ago, J.R. said:

Interestingly whilst that shear plate is a different construction to the one in my link which fits my two compressors both of their part numbers are listed in the advert for the other shear plate so I believe that they might be interchangeable.

 

Or perhaps the complete Delphi and Sanden compressors are interchangeable and carry the same VAG part numbers but the individual parts are different.

 

I think my hub would fit with minimal adaption unless they use different splines, it is of a lighter construction which is an advantage because there is less inertia and its the constantly reversing acceleration/deceleration forces that can destroy couplings like this.

 

Looking at the mass of that one and reading of the rivets becoming loose I can easily believe that they could fail when the compressor is in perfect working order.

I think they have multiple compressors from different manufacturers under the same p/n. I had a lot of trouble trying to track down a replacement pulley for mine as it seems to ve an uncommon one (can't for the life if me remember what brand). I ended up sourcing the pulley from a German website who listed it as a Mercedes spare.

I have to count myself very lucky that my compressor that failed I kept for spares, it was I believe a Sanden SX16, I then bought a Chinese one using the VAG part number, it looked identical, this failed very quickly & through the usual Chinese reluctance with warranty, having to send the old one back I did perhaps an even stupider thing of ordering another.

 

When it arrived before degassing I had a good look & discovered that I could simply fit the drive hub from the new Chinese one to the old one so I chose to do that to not waste my R134a gas.

 

That too failed within a couple of months, was the shaft damaged from spinning? Was it always like that? Were the Chinese alloy hubs not up to it? I really didn't know but was selling the car.

 

So I salvaged the original VAG drive hub/shear plate & fitted that (glad I had kept the old compressor) and threw away the old junk compressor, it lasted long enough to sell and maybe it will last for ever, who knows.

 

In the meantime my luck was still with me as my Yeti uses the same pump, so I ordered the hub/shear plate I linked to from Ebay & will fit it to the second unused Chinese compressor and keep it as a spare, I have not seen the part yet as dont want to do 2 by 2 weeks or quarantine to visit my UK house.

 

I think we can conclude that there are multiple OE compressor manufacturers all supplying interchangeable units to VAG under the same VAG part number but being of completely different intenal construction, the Chinese seem to have copied the Sanden one which is probably made there anyway.

Edited 22 August, 20205 yr by J.R.

For anyone looking at this it might be useful to know the part number of my compressor, which is 5K0820803A, a Delphi  DH5. It also has a code 6CVC 140 on the bottom right of the label.

 

I've sourced a replacement pulley & clutch here

 

Hopefully I won't be looking at this myself in a year or two!

Just a quick update.

 

Finished the job today. About 2.5hrs start to finish at a leisurely pace. Done in situ, access after removing the front wheel is good. Beside the usual tools the only requirement is a circlip pliers. The hardest part is getting the armature with the three legs off. A puller might have helped but I managed without.

 

I attach some pics including the old pulley. You can see where the lobes have worn. The armature with the 3 legs have protrusions at the end of each leg that engage with these lobes. Looks like they simply worn out. I've only got around 85k on the clock so lifetime on these parts looks limited!

 

A/C back to normal.. just in time for the cold weather 😒

 

 

Excellent result!

 

It looks like they are just a spring tension fit in the cups, I had thought they were rivetted, a design that cant cope with the harmonics involved, the constant accelerations & decellerations.

 

My compressors, same part number but Sanden manufactured have rivetted straps but it would take a major seizure for them to shear, far more likely that the hub splines would strip which they did twice to me.

 

I sold the car last week so the problem can not come back to haunt me, I have an unused spare compressor and a new hub drive for it if the same thing happens to the Yeti.

 

When I was regassing it and still learning my way on A/C I filled it too quick with the bottle inverted and there was a hydraulic lock, the engine snatched before I could release the pressure, it will have put stress on the pump internals and the shear plate, time will tell.

 

Pleased that you diagnosed and fixed the problem without shelling out for a garage to fit a new compressor & regas, good on you!

Thanks for the help!

On 22/08/2020 at 13:14, PipH said:

 

You will see there are 3 special bolts on the pulley with dimples in the heads that the 3 leg drive fit into.

 

If the compressor is ok, they must have worn.

 

You could loosen them & rotate 180 degrees to get another life out of them or buy replacements if available.

You will also need the new 3 leg coupling.

 

 

I did not understand what that meant until seeing the photographs of the damaged bolts, I had incorrectly thought that it was a rivetted construction.

 

I am surprised that someone has not machined domed recesses into a batch of standard bolts and sold them on e-bay, there is an opportunity there for someone, much cheaper & simpler than replacing the whole pulley, bearing and hub.

This is an old thread but for anyone looking at this.. the fix doesn't last long, same thing happened again after about 6 months.

 

A more permanent fix seems either a complete compressor change with improved clutch design or perhaps changing just the pulley & clutch to improved design. The original pulley is not compatible with the improved clutch.

 

Hard to source however, this seems to be an option:

 

http://www.aliexpress.com/item/1005005497886208.html

 

I'm dubious of the quality but not many other options. Might give it a go (or try a breakers yard) & report back..

It does not have a clutch.

 

I have used one of the Ali-express shear plates and it failed in about 6 weeks, the splined hub was made of cheese and stripped out, if I replace one now I fit the hub with a high strength Loctite.

 

You did not say what your failure mode was.

 

I was correct about my bad regrigerant filling having stressed the shear plate, it failed about this time last year, I used the spare hub drive that I had, the ali-Express one with the spare pulley that I had as it was compatible, what I didn't know was that the bearing was rumbly.

 

My shear plate came from Eastern Europe without the pulley, I might try to source a compatible Ali-Express one with pulley and try that, do you have a listing suitable for the VAG pump? That one does look identical.

Edited 24 June, 20232 yr by J.R.

Same failure mode as previous, worn lobes on the pulley.

 

Might check a breakers yard & failing that try the alixpress  option.

 

I've yet to verify but a lot of the Delphi compressors seems to have similar, possible interchangeable clutches & pulleys.

There is no clutch, it's a shear plate. Completely different things.