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VW Air Conditioning pump repair

This article was provided courtesy of
www.golfmk4.co.uk
Please visit them for more Audi A4 articles

Many Golf/Bora models are fitted with an air conditioning pump made by a company called Sanden. After approx 100000 miles of use the electromagnetic clutch on the pump can fail, resulting in a screeching noise being heard and a likely hefty repair bill if the problem is diagnosed by a VW dealer.

How can I tell if my pump is made by Sanden?

The Sanden range of pumps look like this :

The alternative manufacturer of the VW A/C pump is Zexel and their pumps look something like this:

Unfortunately, VW dealers do not like to work on air conditioning systems and will often sub contract out any work to a local air conditioning specialist. A consequence of this approach is that the only likely course of action that a dealer will recommend is to replace the complete pump even if this is not actually the most cost effective solution to the problem. A replacement pump assembly will cost in the order of £600 from a VW dealer. Even a new clutch assembly will cost around £200 from a dealer, and unfortunately it is not currently possible to purchase any major components for the Sanden pumps from any other source.

How can I repair my pump for less?

However, all is not lost! If you really need to replace the complete pump and the vehicle is out of warranty, try to obtain a replacement pump from Hella Climate, where you can likely half the VW cost for the same pump. Bear in mind that you will still need to pay a specialist to de pressurise and then refill your air conditioning system with refrigerant, even if you fit the pump yourself.

An alternative approach is to repair the existing pump in situ. The actual failure of the clutch results from the internal spline that connects the clutch hub to the input shaft of the pump. The spline wears over time until there are no teeth left to drive the pump so even though the clutch still operates, the pump shaft remains stationary. The clutch hub is retained on the end of the pump shaft by a nut, but when the spline has worn out then the nut is quickly undone by the speed difference between the hub and shaft, consequently the nut will probably be missing by the time you are even aware there is a problem with the pump.

Diagrams of a generic Sanden pump can be found here

It is possible to repair the pump by simply replacing the end plate/hub of the clutch with a replacement part from a secondhand pump, which can normally be picked up for £50-100 from the likes of Ebay. This has the advantage that there is no need to split the sealed refrigerant system, so long as you can work on the pump within the engine bay. To access the pump, first the engine cover and alternator must be removed. The pump is retained by two long bolts which are inserted from the side of the drive belt.

If you are replacing the clutch hub on your pump you will need a new retaining nut, for which you can purchase a complete clutch fixing kit from a VW dealer (e.g. part no. 1J0298912). Note that this kit also contains a selection of shims that are used to adjust the free clearance in the clutch. However in my experience it was not necessary to reset the shims so long as the clutch hub has not previously fallen off and allowed the shims to be lost.

If you have had any problems with your pump, it is still advisable to get your system serviced by an air conditioning specialist. Another cause of problems for VW pumps can be due to lack of lubrication, in which case the pump seizes up. By getting your system serviced regularly (e.g. every 2 years) you can ensure that the pump is kept lubricated and prevent this problem from occurring.

This article was provided courtesy of
www.golfmk4.co.uk
Please visit them for more Audi A4 articles

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