Mercedes A class W169 Diesel Auxiliary drive belt replacement.

[@batchrocketproject4720]

I did this as a hobby mechanic and it was quite demanding. Even finding the area and identifying the pulleys takes time (this video is one of the best at showing things, thanks). Before you can even begin you have to remove plastic skid panels from the underside of the car. In my case the old belt was broken and shredded and I spent the best part of an hour removing belt fragments that were jammed under pulleys. After much trial-and-error (lasting an hour in my case) I agree totally with the order of fitting the new belt suggested in the video: use a long hook to get it over the upper water pump pulley first and then around the crank (lower front large pulley). Next, use a long hook to continue from the top of the water pump pulley over the next plastic guide wheel (above the tensioner and to the front of the car) Note that this smooth plastic pulley has the ribbed side of the belt against it (the only one of the three plastic pulleys that don't contact the belt back). To weave the belt over the tensioner and other plastic wheels you need a long hook. Getting the belt around the alternator and onto the cooling pump pulley is difficult, the belt is very tight and the tensioner spring very strong. You need a very long 15mm spanner (in my case I cut one from some steel flat bar but only got one or two goes before having to regrind it as the tension is very strong and wore the mild-steel bar quickly). Some videos show two spanners being hooked together to get the length (a 15mm ring spanner over the tension wheel bolt with a ring spanner looped over its open end and used as a lever). I was able to get that method working but only after trying many spanner combinations as spanners are not flat and there is hardly any room to allow for tools. It would probably be quicker to go and buy a long spanner. I was able, with some physical effort, to get the belt finally seated on the curved rim of the cooling pump pulley before levering it over onto the ribbed seat bit-by-bit, carefully with a blunt screwdriver. In my case this was barely the start of the job as, despite checking the pulleys all rotated freely (except the crank) and that things appeared to be lined up, I hadn't spotted the reason why the belt had failed in the first place. The spindle of my tensioner wheel had ground its seat oval. In my case the result was instant shredding of the new belt when I started the car. I was able, eventually, to replace the tensioner assembly but it took me several days and involved removing two engine mount bolts from inside the wheel arches. Also, unhook the exhaust or it hinders the 2 or 3 inches of space made available by lowering the engine. When the cooling pump is removed, the cast housing it, that also wraps around the alternator, is the part that carries the tensioner and guide pulleys and is what I needed to replace. The replacement assembly is attached to the engine by three (male) torx-head bolts (E12 I think) far towards the front where the water pump is, jammed between the engine and the car floor. Even with the engine lowered you cannot see the bolts but have to feel for them (or rather for the recesses they are sunk in, except for one at the side of the casting which is just visible), armed with knowledge of their position got by inspecting the replacement part. It took at least an hour to remove the three bolts. Space is so limited, there is little arc to turn the socket wrench and the close thread need hundreds (not an exaggeration) of short twists to remove (a friction-less ratchet would have helped as I often had to remove the socket and re-seat it as the ratchet would tighten the amount I had just loosened otherwise). after a while they loosen enough that you can just about turn about 1/10 of a turn with fingertips pressed on the socket with the wrench removed. It is tedious and difficult. Putting the new part back on was slightly easier than removing it, mostly because your hands have learnt where the bolts are. It can be done but expect to take time and patience.

[@BurnedOutGarage]

Excellent input thanks! Although you say you are a hobby mechanic - your write up suggests to me you are an engineer of some sort?! Very detailed explanations how the task is to be achieved etc.

[@batchrocketproject4720]

@@BurnedOutGarage That's very kind praise, thank you. I have a science background but not engineering. I studied every youTube video I could find before starting, often pausing tiny segments that caught important views (I wish I'd found this one before, it is definitely the clearest). I wanted to share my experience as I'd scanned all the comments of other videos hoping someone had done a similar job and had some information that would help. It might help someone. Thanks again, and keep up the good work!

[@JurisKankalis]

@@batchrocketproject4720 Jeeeeeeeeeesus man, thanks for the long comment. The video is not of the best quality - it would be much better to film ALONG the work being done - not after it - and the guy literally points at the tensioner bolt while messing up the camera - but I guess this is the level of work that does not allow for filming AND doing at the same time. Will have to do this appararently tedious work now here in Latvia, have about 3-4 hours, will try lifting the car with drive-on ramps out in the yard - it's dark and wet and cold - mid February - but heck, I've replaced belt on the other car in the family - an Audi C6 3,0 diesel - about twenty times, incl. on the road - and this cannot be much more complicated. That would just be impossible. Can it? Well. About to find out. Thanks once again for the input, greetings from Latvia.

[@batchrocketproject4720]

@@JurisKankalis main tip is finding a long 15mm spanner for the tensioner, it has to be quite straight too. If you get stuck try using a hammer to bend the spanner ring so that it's parallel to the handle, and hook two together if not long enough. It's definitely doable in an afternoon with patience. I'll be interested to hear how it goes if you get chance to report back. Good luck!

[@howardelliott8136]

Just replaced A Classed belt found your video very helpful ..I however did it on my drive .. I did use a "windbag" to jam the belt in place on water pump and top jockey wheel which saved the belt keeping slipping off..thanks H

[@BurnedOutGarage]

Thanks Howard. Sounds like a good method!

[@DippySippy]

@@BurnedOutGarage did you have to remove the engine ? Mechanics are charging a fortune just to replace the timing belt. Like 1000s for a 14 pound part

[@albertnel7468]

Thank you for the hints. It saved me a lot of time.

[@oldlifestylebyandrei]

Many thanks for video! Is possible to replace the tensioner without take down the engine?

[@bewarduzi9563]

Respect 🫡

[@MercedesW169]

Good afternoon. I'm filming about this car. The repair was not difficult.

[@BurnedOutGarage]

No not at all 5-10 min job in the ramp. I was moaning a bit as I tried to do it on the guys drive on my back in the rain 😂.

[@RealDixonPeter]

Actually pretty hard time consuming job especially when you need to do the the 3 pulleys

[@BurnedOutGarage]

@@RealDixonPeter Yeah totally I thought it could have been made a bit easier I know multiribs last quite a while these days. I’ve fitted a lot of b’stard v belts on front wheel drive cars but I couldn’t believe how trapped this one was.

[@guraykaraca450]

I love A class,thanks

[@affiyanrosalan2012]

thank you 👍🏻

[@BurnedOutGarage]

No problem.

[@FernandarodriguesteixeiraTeixe]

Eu tenho uma Mercedes a 170 e a centralina das portas está avariado só que eu não sei onde fica pode me ajudar obrigada

[@BurnedOutGarage]

Hi sorry for the late reply I had to translate to realise what your comment meant. The door control unit of each door appears to be fitted in each door on W169 chassis. Oi, desculpe pela resposta tardia, tive que traduzir para perceber o que seu comentário significava. A unidade de controle de porta de cada porta parece estar instalada em cada porta no chassi W169. If you go online you will find various Mercedes WIS manual uploads which will allow you to test the wiring around the module and find the problem. Se você ficar on-line, encontrará vários uploads manuais da Mercedes WIS que permitirão testar a fiação ao redor do módulo e encontrar o problema.

[@FernandarodriguesteixeiraTeixe]

@@BurnedOutGarage Obrigada Mas a parte que preciso e a que abre as portas com o comando que eu não sei onde fica obrigada

[@RolandKontson]

For getting an old belt off or a new belt fully on, as to not damage the belt. This autodoc video showed that one of the pulleys can be manipulated with a wrench to lessen the tension temporarily as you apply torque to it: kzbin.info/www/bejne/g16bioaPfqlnd8k