Good morning all. There’s so much good info on here but I can’t seem to find an answer to my problem. I’m new to VW bus ownership (well classic cars in general) and it’s been a pretty steep learning curve but I’m getting there I think. It’s been made all the more interesting with the fact that I decided to drive to mainland Europe 3 days after buying it and have been stuck/lost here ever since due to Covid. I’ve certainly gotten to know the bus pretty well So my issue is my alternator charge whilst driving. I recently fitted a leisure battery hook up and I have a LED display telling me the voltage of my leisure battery. It’s connected to the main battery via a simple split charging relay. Whilst driving, the maximum I get is 13.1V. I tried changing the voltage regulator for a Beru one, my alternator light on the dash come on and stayed on. Obviously no good. I then bought another regulator and it was good for a few days. Plus 14v whilst driving etc however again, on the 3rd day, the alternator light came on the dash and stayed on. I have gone back to the original regulator for now but I’m hoping someone can point me in the right direction. It’s a 79 2.0 type 4 bus with external voltage regulator. With thanks Mike
The usual other problem is worn alternator brushes, if the light comes on, and changing the regulator doesnt stop it. Over on thesamba.com you can find a description of an alternator test procedure. I just googled "alternator test procedure site:thesamba.com" First and simplest they suggest checking the belt is tight... From one of the links there, they describe a procedure where you remove the regulator and then connect various wires either together or to the battery *dont short anything to chassis or goodbye alternator if its running. https://www.pelicanparts.com/techar..._troubleshoot/914_alternator_troubleshoot.htm Basically if the field winding DF+ is at a reasonably high voltage, the output of the alternator should be high enough to charge the battery. The wierdest one I had was using the bus with a loose battery clamp. Each time I started it , it was OK. I drove it 17 miles and stopped at work. In the evening it started and I went home down a bumpier road. The alternator light came on after about a mile. Battery voltage showed 17 volts on the starter battery... So I smacked the negative battery clamp down and tightened it up. Problem solved. This is then followed by the buying of a replacement alternator and at least in the USA, this is then followed by the positive lead of the new type 4 alternator shorting out and burning wiring because the positive stud is too long on the new alternator.
Thanks for your reply. the thing is though my alternator light isn’t coming on when I use my old regulator, it’s just a really low charging voltage whilst driving. The alternator light only comes on when I’ve changed the regulator to a new one. I do have a new alternator on the road with me but I’m reluctant to change it out due to having a good charging voltage with a new regulator (before it makes my alternator light hard latch on). I’ll have a read through the procedure you suggested and report the findings back
The hard on alternator light may also be a broken wire between the regulator and the field winding - you fit the regulator, and the wires are disturbed so they connect. Then they "relax" with vibration and part contact. I have seen a few cases where the VW crimped on spade terminals are gripping the insulation but the wire inside is broken. If you have a crimping tool and a brave attitude , what you do is try and pull fairly hard on the crimped on connectors. If they feel 'soft' with a bit of give like you are stretching the PVC, or they fall off then there is a problem there that needs fixing...
I recently fitted a 90Amp alternator off a T4 Caravelle to one of my Type 4 buses. When the leisure battery is run flat the alternator hates it and burns itself out. I hire my vans out, and was going through 2 of the stock alternators in a year. The 90Amp alternator gives a great consistent voltage and sure it will last longer being a much more modern design. You do have to modify the adjustment arm as the 90Amp alternator is a huge beast and just fits.
Interesting modification; it would speed up the battery charging and I could remove the useless solar panels and wouldn’t need to replace them. Did you use the T2 or a T25/T3 fan shroud? What about the cooling elbow from the shroud, could you fit it? Did the pulley line up? What size fan belt did you use? Too many questions….
This is from a recently fitted engine. As you can see I had to cut the tinware to allow for the alternator fan. I blanked off the cooling elbow too as all modern alternators have their own fan which I imagine does a better job. The fan belt is stock, although I would probably use a longer belt in future to make adjustment easier. The fan shroud is the CJ shroud, although will be doing to my CU shrouds. The bottom bracket is a perfect fit, but the top is needs a new bracket made up. Would like to see if anyone else knows of another high amperage alternator that fits.
The 70amp alternator had a fan but retained the cooling elbow so that it was drawing air from the fan shroud, without it the alternator is sucking hot air from around the exhaust and heat exchangers and blowing it into the engine cooling fan inlet. Thanks for the info, but it’s back to the drawing board for me.
