kikiturbo

Hi,

I saw a lot of discussion on the AWS pump failures on E10, which is the same problem that we had on earlier EVO's. Even though the pump is a bit different on the E10, the problems are the same, if not worse.

First.. here is a vid I made, describing the overhaul of the pump.

<iframe width="560" height="315" src="http://www.youtube.com/embed/ZrYjQat4KGE" frameborder="0" allowfullscreen></iframe>

The video covers the pump failure, and the procedure to overhaul it. The important thing is that all pumps can be fixed, even Evo 10 pumps, and if sealed properly, they will last..

Let me do just a quick overview of the falures, that we have found:

FIRST AND FOREMOST: The reason for almost all the failures is corrosion and the funny property of aluminium oxide to increase in volume..

1. Pump failures.
The AWS / AYC / ACD pump uses a simple gear pump, producing about 20 bar of pressure. The pump is constructed in a form of a "sandwich" with a thin aluminium plate between two halves of the pump. The problem occures when you get water and road salt between the sections of the pump, which corrodes and the pump "swells" a bit. This increases the fine tolerances in the pump and it starts producing less and less pressure. Normally, while the oil is thick in the winter you do not see the problem, but come spring and summer, oil gets thin and pumps start to fail.

Solution is in the vid... Pump needs to be opened, corrosion cleaned, usually the pump plate and the seals need to be replaced.
The biggest problem is, usually, the actual dissasembly, as the bolts holding the pump togeather corrode along their length and stick to the housing.. A bit of cutting is needed but even though it looks nasty, the pumps work..

here is an example

2. Valves breaking..

The valves are not fragile, as it is thought... but the problem is again the corrosion.. They tend to corrode around the entry point into the pump body... right up to the O ring.. They get stuck inside the pump, and form a crack around the base of the valve. On Evo 10 this is very often because the pump sits lower and there is not enough room for water to flow away.. but it just sits on the bottom around the valves..
Broken valves can be removed from the pump body, with more or less trouble.. Getting replacement valves is the problem..


Protecting the pump

I have looked into making a protective box for the pump, but have stopped because I feared issues with heat management..
However, the pumps I have fixed, I usually seal with silicone + some real heavy grease around the valves,... and that does the trick..

My suggestion, for those that still have functioning pumps is to spray the pump with some grease based spray.. like motorcycle chain spray... That can be easily removed later if you need to rebuild the pump, but will protect it from the elements..
If you get a new pump or a refurbed one... just seal all the gaps with silicone, put some heavy grease around the valves.. that should work..

starmax

iTrader: (1)

Just ordered some ACF-50 Anti-Corrosion Block Compound to spray on my freshly replaced pump, we'll see how it works (thanks Ryan!)

kikiturbo

my suggestion is to first seal the pump with silicone, add some heavy grease around the valves...

starmax

iTrader: (1)

thanks for the tip! Any special type of silicone? I doubt I would need high temperature silicone...

Also, in the video you mentioned the pump is placed in the front for the US cars, but for the Evo X it is behind the passenger rear wheel. Any chance that protective box would work for US Evo X's?