After having a couple of breakdowns in the VW T25 I did a fair bit of research online to try and figure out what had caused the engine to cut-out. I put a post on the VW T25 Club Facebook group, fellow members suggested it was most likely related to a fuel blockage – or an electrical problem associated with the distributor.
As far as I could tell there was no problem with the fuel getting through – the fuel lines had been replaced only a few months ago, and the filter looked to be clean. I had a thorough examination of the distributor which was new to me as I hadn’t looked further than the distributor cap and rotor arm previously. I noticed down the side of the distributor three thin wires came out of a gap in the side – and two of these had the sheath worn away to bare wires which were very close to the metal of the distributor body.
After more research I determined that these were connected to a component within the distributor called a Hall Sender – which I’d never heard of before. Reading up on various forums I discovered other people had had the same problems as me with the engine cutting out within minutes of starting a journey when the engine was already warm. They had changed the Hall Sender which had rectified the problem.
As the wires and connector on my Hall Sender were in a bad way in my VW T25 I decided I ought to start by replacing it, it needed sorting anyway. The wires were too short to repair.
I tried various suppliers of VW T25 parts to buy a replacement Hall Sender. In the end I bought the part from Just Kampers.
The new Hall Sender
Before removing the distributor I needed to get the flywheel in the engine to ‘Top Dead Centre’ (TDC). I opened the flap behind the number plate and removed the plastic grille covering the flywheel by removing three bolts. This also had a plastic scale attached which came off, I reattached this with two of the bolts.
Location of the flywheel – behind the grille
Next I had to crank the engine round to the TDC position. The flywheel has a small notch which indicates this, I added a small blob of white paint to the front of the flywheel so this was easily visible. I then put the gear box into fourth gear and released the hand brake. Using a large socket ratchet with a 13mm socket I put this onto the bolt in the centre of the flywheel and cranked the engine around until the white dot aligned with the 0 on the scale. The van moved forward slowly as I cranked it around. Once in position I took it out of gear and reapplied the hand brake.
Flywheel in TDC position
I then removed the rotor arm, took off a plastic cap underneath it – and put the rotor arm back in place. There is a small notch in the top edge of the distributor indicating the TDC position which the rotor arm should be pointing to, which it was. The distributor was now in the right position to remove.
Rotor arm alignment
To release the distributor I first disconnected the wiring connector, and the two vacuum pipes. I then used a small 10mm spanner to turn a hex shaped bar at the base of the distributor, on the left. This was very fiddly, however eventually the distributor became loose and I could wiggle it out.
Loosening the distributor
Next I plugged the hole the distributor came out of, to ensure nothing fell in. The best thing I found was a GU10 spot light bulb which fitted perfectly.
The plugged distributor hole
The removed distributor
For the next stage – dismantling the distributor, I worked at the table in the van. I removed the rotor arm again, and now had to remove the round plate below this. The first thing to do was remove a circlip, unfortunately someone had clearly had this apart before and replaced the original circlips with the internal type – when they should have been external clips. This meant that the holes were half covered inside the groove, and I couldn’t get the clip off. I had to use a small screwdriver to lever it off, luckily the replacement Hall Sender came with replacement screws and circlips.
Removing the distributor plate
There was a small metal washer to remove, then the round plate had to be removed. I could see it had a tiny pin against the spindle in the centre, to stop the round plate rotating. The plate was well and truly stuck so I applied WD40 then very gently levered it upwards with a screwdriver, working my way around the edge slowly to ensure I didn’t bend the plate. It gradually came loose. I ensured I didn’t loose the pin and removed the plate.
Distributor plate removal
I now had access to the Hall Sender. I removed the vacuum unit off the side, and the clips which held the distributor cap in place. I had another internal circlip to remove which I again had to lever off. The Hall Sender was attached by three screws to the casing of the distributor, after removing these I wiggled the old Hall Sender off.
The old Hall Sender before removal
The distributor after removing the old Hall Sender
Next I fitted the new Hall Sender, which was slightly different in appearance, presumably as it was a reproduction of the original Volkswagen part. This took a bit of levering to get it in place so the three screw holes lined up with the holes in the distributor. Once they did I put the screws in place, including the clips and vacuum unit.
The new Hall Sender fitted
The connector on the new Hall Sender wouldn’t fit into the gap in the side of the distributor so I laid the wired in the gap and let it hang loose for the time being. When refitting the vacuum unit I first had to unsure the arm from this was hooked over the stud on the new Hall Sender. I then screwed this back to the distributor.
I replaced the first circlip using one of the correct external ones which were included with the new Hall Sender. I then gently pushed the round plate down back into position, keeping the notch in the centre aligned with the groove in the centre spindle. Once fully down I used a small punch to tap the pin back in place, and put the other new external circlip in the groove of the spindle.
Now I was at a stage to refit the distributor into the engine of the T25. I put the rotor arm back on and rotated it so it aligned with the notch on the edge of the distributor. I wiggled the distributor back down into place until it was fully down, ensuring the notches on the very bottom of the distributor slotted into the holes.
On inspection of the Hall Sender’s wiring connector this was totally different to the connector it needed joining to, as it did warn on the Just Kampers website. I chopped off both the connector from the Hall Sender, and the connector it needed to join to. I then used small terminal block to join the wired after tinning the ends with a soldering iron. I wrapped a little insulation tape around the wires coming from the distributor to protect them from wear temporarily.
Wiring the new Hall Sender
I retightened the clamp of the distributor next. I then removed the rotor arm, put the plastic polo shaped cover back in place, put the rotor arm back on, clipped on the distributor cap and reattached the vacuum tubes. I was now at a stage to try starting the vehicle.
The distributor back in place
I turned the ignition key and to my surprise it started up first time. The T25 sounded to be running fine, however I now needed to setup the timing before it would be ready to drive again.