Good day everyone

I have this problem with my car. A time ago the thrust on the crank with the center main bearing worn off. This resulted on play on the crank and changing gears is hell as the clutch doesn't release properly. Last week it started again and I have done only about 30 000KM on the crank and bearings.

I'm from South Africa and the car I'm driving is a VW Golf 3 with a 1600 block. The previous crank ran with the standard size bearings. What I did as well to prevent possible damage again was to replace the self adjusting clutch cable, the release bearing, push rod, the clutch and pressure plate as well. Is there something I'm maybe missing? I don't drive with my foot on the clutch.

Any sugestions?

Thanks.

 

Maybe I'm thinking about this all wrong? What does the crank shaft have to do with shifting gears? I dunno mayube I dunno as much as I thought I did but you shift with tranny and linkages, not with the crank shaft that connects to rods to move pistons which are moved by fuel and spark which lites off fuel which makes the car "go". Maybe I'm missing something.......

 

Good day.

I will explain quickly. What happens when I step the clutch pedal is that the crank gets pushed away (the crank has some play on it) in resulting that the clutch plate doesn't disengage properly from the pressure plate. If the clutch doesn't disengage properly it will struggle on changing gears. What I'm trying to figure out is what is causing the thrust on the centre of the crank to get worn off.

I will quickly upload a sketch...

 

Tried to upload the images to this sites photo gallery. Doesn't work. Here is a link to the photo's:
http://www.mikotime.co.za/forum.html

 

Let me explain the blue arrows on the 1st image. When the clutch pedal is stepped, the push rod pushes in the direction of the blue arrows. It pushes the pressure plate (bolted on the crank) away from the clutch plate so that gear shift is possible. But what happens here as well is the crank moves. In result the pressure plate is not properly disengaged from the clutch plate.

What I found that causes the crank to float to the other side is that the center bearing's thrust gets worn away and eventialy result in the floating.

Somebody told me to prevent the wearing of the thrust bearing is to replace the clutch components (clutch cable, release bearing, push rod, clutch plate and pressure plate), which I did previously when I did had the problem. They said those components when faulty can put unnecessary stress on the crank and bearings and eventualy the bearings fail. Another possibilty could be a bad material when manufacturing these bearings. But I'm not sure as these are the original bearings sold by the car manufacturer.

What else? Any one has suggestions?

 

Another thing worth mentioning is when the engine is running the reverse and the 1st gears is impossible to shift when the clutch is stepped. But as soon the engine is off, those gears can work. I had to drive like that for the last week. When getting to a robot or stop sign, I have to switch off the engine, shift it to 1st gear and start the car again.

 

i have seen this on ahonda of my freinds hereplaced thrust bearings and it lasted a few weeks
time fore a O.H. or a good used motor crank is worn out

 

Thanks every one for replying. The torque values on the caps I got from the dealers as follow: 75 newton metre on the mains and 40 newton metre on the big end bearings. As for the seals, I always replace them when working in the area of the crank and bearings, saving me future work on leaking seals.

The crank was previously on standard size, but when it worn off, the engineering place sugested to take it to the next size. So they machined it to 010 with an over size thrust. On the other hand when I fit these parts I take extreme caution not to make any damage.

The linkages I did check it is fine. See, it is only the reverse gear and 1st gear that is impossible to push when the engine is running and vehicle is at complete stand still. The other gears move bit difficult but they work though.

I know that replacing the clutch components wont help the loose crank from sliding. See what I did here was the previous time is I got another crank and new bearings. Some one suggested then replacing the clutch components would prevent the bearings wearing off again. He said if the clutch components is worn, it is a matter of time before the new bearings and crank start wearing again. Is this possible?

Can you explain where the throw out bearing is? Is it part of the gearbox?

One last thing though. The car is using a self adjusting clutch cable. I have heard that these cables do give problems. It was suggested that I try the old manual adjusting clutch cable.

 

Hi there.

Just want to figure out what you explained. It sounds to me that you are talking about the push rod. I don't know if things differ from country to country. On my gearbox it has the fork. The fork then presses on the release bearing and this again on the push rod which presses the presure plate. The push rod runs within the main shaft fixed with what they call a spricket bush. Do I have it right?

 

I got a good used crank today. It is standard size, so no machining required. Got the new bearings as well. Lets see what it does. I got another clutch cable as well, but it is the manual adjusting cable. Lets see if it lasts this time. Will keep updated.