Components and Assembly
Gearbox Conversion from ACS(Auto clutch less)to Fully Manual with Clutch
As many of you will know from what you have read on this site the only difference between ACS(Auto clutch less) and the Fully Manual gearbox version of the A class W168 is the activator module fitted under the nearside wing which activates the clutch atomatically between gears saving the driver having to manually dip the clutch when changing gear.
This when the car is new works well but as the years pass and the age of the car increases so problems develop which can cost a lot of money to put right with the new activator module costing over £1000.00 plus fitting.
In a large number of cases all that's needed are new carbon brushes for the electric motor portion of the activator and these are available via the link on my page mypage 59b
However in a few cases the activator's life span has been reached and only a replacement unit will cure the problems if the car is to remain a clutch less version but at £1000.00 this can be out of the question for economic reasons .
This invariably with the older A class is more than the car is worth, and yet many of these cars are in very good condition and owners are very reluctant to part with them without a fight.
There is little wonder therefore that owners have come up with a solution which is a cheap way of keeping the car on the road in a fully serviceable condition, CONVERT THE CAR TO A FULLY MANUAL VERSION, yes this can be done and the cost is very little when compared with the alternative solution, and surprisingly is not a difficult or long job providing you have obtained the necessary parts.
The basic requirements are a pedal box which includes the clutch, brake and accelerator pedals which comes in one unit and are available from any manual version of the A class being broken for one reason or another.
The only other item you will require is a hydraulic pipe to connect the clutch master cylinder to the slave cylinder at the bell housing below the car. These can be made up at any good garage as hydraulic fittings are standard or you could purchase the part ready made from Mercedes parts. Quoting that you need a 'Replacement hydraulic pipe, that goes between the master cylinder and the clutch slave cylinder.
There is little more I can add to this conversion but I will add e-mail received from Colin in Australia who has undertaken the job and is very pleased with the outcome.
I would say at this point that I will retain Colin's e-mail address and should you have question which I cannot answer will contact him on your behalf.
Colin's problems starter when the car let his daughter down, albeit she did manage to get home, needless to say he became worried that she would get stranded with the car.
He worked on the car and changed the carbon brushes in the motor of the activator but that did not cure the problem, it being considered that the problem may well be on the PCB (Printed Circuit Board) motor section of the unit, had he been in the UK it might well have been possible for ECU testing.com to recondition the unit but I have at this point not contacted them re that possibility.
Colin therefore decided to convert the car to a fully manual A class version and set about getting the parts.
I will duplicate Colin's mails to me at this point :-
Sorry for the delay but it has taken some time and a lot of diagnostics of the ACS to resolve.
I replaced the bushes with some bought from the supplier in the UK but still no joy. Eventually I discovered that that I had something further wrong with the system as I was not getting a proper voltage at the brushes meaning there was something probably wrong with the electronics of the unit.
With the prohibitive cost of the ACS unit being close to the value of the car it left little option but to try the conversion to full manual. After one aborted attempt to get a pedal box from the UK (didn't arrive) I finally got one complete with clutch master cylinder.
Finally good news to report. I am now the owner of a FULLY WORKING, FULLY MANUAL A class 160 Mercedes.
I put the pedals in last weekend. Instead of putting the whole pedal box unit in all you have to do is, put the new brake pedal where the old Auto style pedal was( a fiber pin holds it in place) and then put the clutch pedal in place with the same arrangement. The pedal box fittings are exactly the same which makes it very easy. Remove a grommet from the firewall to put the master cylinder for the clutch in and hook it up.
The only problem was always going to be the hydraulics. I just took the old line out and took it to a local manufacturer of hydraulic pipes and had them make up a new hose about the same length but in stainless steel / Teflon pipe with heat protection over it ($135). It surprised me, but they were even able to match the Mercedes fitting's which I didn't think they would be able to do.
Just finished putting it all in, and she drives like a dream as a manual, as a matter of a fact I prefer it this way it feels more normal. As they say you have to leave the faulty ACS unit in place to complete circuits which means you have the 'F' on the display but this is small price to pay to resurrect the car. All in all I would thoroughly recommend this option as it is relatively cheap and very easy to do in just a couple of hours once you have all the parts.
Just one other thing, I have found the easiest way to bleed the system whether it be ACS or full manual is to reverse bleed.
Get a large syringe, about 60ml, and about a couple of feet of plastic tube (6mm or 1/4"). Fill the syringe and tube completely with brake fluid ( no air bubbles in the line) and then attach to bleed valve on the clutch slave cylinder under the car. Open the bleed valve and slowly depress the syringe forcing the brake fluid back through the line. It helps if you have a 2nd person monitoring the reservoir to avoid overflows, otherwise leave the syringe and pipe attached and just shut the bleed valve to check yourself. Usually one syringe worth is enough and you have a perfectly bled system.
Well done Colin,
Couple of questions
Did you disconnect the electronics or are they still connected?
Have you tried disconnecting them to see if the car still starts?
Have you considered visiting a Mercedes, main Dealer or an Independent Mercedes garage to try and delete the 'F'
Yes the method of Bleeding, priming the hydraulics is sound in fact I have suggested that method to owners previously, at least that way you don't chance leaving air in the system.
When you say disconnected the electronics I presume you mean the ACS unit itself?
No it is still connected to enable all the circuitry to be complete. I believe without it the car will just lockout and not start.
To this end I have removed the relay for the ACS and it does not start.
In relation to trying to have it deleted by a dealer, that is a thought, but the closest dealer to me is 80km (50 mi) away. Also I am always put off by Mercedes dealers, as you have stated many times all they seem to be interested in is getting the money in their pockets and not really helping you with your problem ( doesn't seem to change whether in Aus or UK).
Seriously for those with a similar problem of a totally faulty ACS I would seriously recommend the conversion. It is very easy to do, certainly solves the problem and is not very expensive. Furthermore no more worries of the ACS unit having a fit, as testified by the number of people who seem to have this happen to them.
I have sent 5 photos
New pedal box that I bought but with old brake pedal in situ.
When you compare this box with that already in an ACS vehicle it can be seen that pedal box's are identical.
As manual A class are rare in Australia, I sourced my Pedal Box through a wrecker, on E Bay UK Motors. Cost of about 20 GBP. Even for me with freight all up cost for conversion was $235 AUD (150GBP).
2. This photo clearly shows why you don't want to replace the entire pedal box. The very top bolt hole A is all but impossible to get at without removing the entire dash. As stated before, the preferred and EASY way, just replace the pedals and use you existing brake light switch.
You can also see in this photo the fibre pin B (partly removed) retaining the brake and clutch pedals. It can be a bit hard to remove from the brake pedal already in the car due to its location but persevere it will come it is just awkward.
3. New pedals in old box. I have read other people say they have had trouble with the clutch return spring not allowing the pedal to return properly but haven't found that yet with my conversion. In any case the return spring can be removed and clutch will work just as well. I have found it to be a very light clutch with very easy action. Remember to reset the brake light switch by pulling the white centre pin out over the ratchets until it is fully extended.
4. This shows the new Flexible hydraulic hose from the master behind the clutch to the slave under the car. When making this up order it to the same length as the already existing hose to the ACS unit (best to remove that hose anyway to avoid confusion down the track) The orange cover is a heat protective sleeve, probably not necessary but the mechanism underneath the car is close to the exhaust system (better be safe than sorry).
5. Shows the reservoirs. The original Mercedes-Benz way is to attach the feed tube for the hydraulic clutch to the back of the master cylinder which also serves the brakes (original nipple can be seen).
I personally don't like the single master cylinder, if something happens to one hydraulic system you will loose both.
I therefore used the (small) reservoir and feed tube from the now redundant ACS activator unit, mounting it on the fire wall adjacent to the Hydraulic brake master cylinder with a screw until I get round to I making a bracket to mount it on.
Leave the redundant ACS unit in place and follow the bleeding operation already outlined and providing you have all the parts ready you should be driving the car again in no more than 2 hours.
Also Lofty I would be happy to answer in questions you forward.
I think that pretty well covers it as I said it is very easy and simple. The only down side being the "F" stays on in the display but this is a very small price to pay to have a working car.
DO REMEMBER You must have your foot on the brake and neutral gear selected to start the engine.
Mine had two master cylinders/reservoirs one for the brake and one for the ACS which was located near the left hand wing. All I have done is pull that out and reposition over near the brake master cylinder which is closer to the clutch slave cylinder..
The relay I pulled is marked on your fuse and relay diagram as the K9 relay in the battery compartment. Pulling this gets rid of the display from the dash so I presume it must be operating the ACS unit.
However it needs to be left in place or the car will not start, which means the 'F' remains displayed but this does not worry me.
Cheers & Good luck
Thanks Colin for your input on this page I confident it will help other owners with insurmountable problems overcome them by making the car usable with the manual clutch conversion.