vacuumpumpfix

Modifying Your Brake Vacuum Advance Pump To Avoid Replacement In 300Tdi Engined Vehicles
As some of you may have found out the brake vacuum advance pump on the drivers side rear of the engine block can develop a pretty nasty leak, along with this leak will come a very spongy brake pedal. On the inside of the pump is a diaphram which is meant to contain the oil, however the oil can get past this and slowly work away at the cap on the end of the pump that is only riveted on. Once these rivets become loose it leaks oil. A replacement pump is anywhere between $400 and $500 this modification cost less than $10 and once done can be repaired easily at any time. So what is this fix you ask? Its very simple realy and only requires a few basic tools and some basic mechanical knowledge. All this fix involves is removing the pump, drilling the rivets which hold the cap on, cleaning the pump, cutting a homemade gasket and refitting the cap with some stainless steel bolts and nuts. Read on and get all the details. Tools and Equipment Required - Socket and spanner set - 3/16 drill bit - Gasket paper (to cut your own) - Drill press - Gasket sealant - Degreaser - Clean rags Parts Required - 6x3/16 stainless steel bolts, nuts and washers (20-25mm in length) - Gasket paper - Vacuum pump to engine gasket.
Step 1- Before you begin you need to set your engine to top dead centre. The method of doing this can vary from model to model so it is best that you refer to a workshop manual in order to do this. Once the vehicle has been set at top dead centre you can begin removing the pump. You may need to undo some hoses and lines to get better access to the bolts, just remember where each one goes and dont loose and bolts or nuts. Once the bolts securing the pump to the engine block are undone it should pull out. Once removed push a clean rag into the hole in the engine block to stop and dirt ingress.
The brake vacuum advance pump is the component in the centre of the photo underneath the fuel line running from the lift pump and away from the engine at 90degrees.	The pump once removed from the engine block.
Step 2- Once removed from the engine the pump will need to be cleaned. Once all the dirt and oil has been removed the rivets can be drilled. Simply cover the other end of the rag and place under a drill press (it is best to use a drill press because it will drill straight down a hand drill will work but a straight hole might not be achieved) and slowly drill the rivets out, be careful and take your time. Once the rivets have been drilled the cap will come off. Again clean the area and ensure no dirt or grime gets inside the pump.
The cap on the end of the pump, in the picture the pump hasnt been cleaned but the 6 rivets are clearly visible.	The inside of the pump once the rivets have been drilled and the end cap removed. (the new gasket is in place) When removed make sure you dont loose the orange rubber seal visible on the inside of the cap.
Step 3- Once you have removed the cap place the pump over the top of your gasket paper and cut around the outside of the pump with a knife, or trace around the pump with a pen and use some scissors to cut the gasket out. Once you have cut it out smear some gasket sealant on the surface of the pump and stick your gasket to the pump surface, the sealant will help hold the gasket in place whilst you cut the centre hole out. Once the gasket is cut smear sealant on the surface on the cap which will mate to the gasket. Once this is done place the cap back on the pump and secure down with the nuts and bolts, be sure to use a washer on both sides, and use nyloc nuts rather than regular nuts. If nyloc nuts are not available use spring washers as an alternative. Once this is done you can refit the pump to the engine. When you do this clean both the surface on the engine and the pump, then smear gasket sealant on both surfaces place the gasket on either the engine or the pump (the sealant will hold it in place on either surface) and bolt the pump back on. Once tightened make sure you remove and securing pins that may have been required to hold the engine at top dead centre. It isnt necessary but bleeding the brakes at the same time will provide a better result interms of braking quality.
The finished pump with the new nuts and washers fitted. With the gasket now in place and the tight seal provided but the bolts rather than the rivets no air or oil will escape from the vacuum advance pump so braking power will now be maintained.