Reverse crunch

[JayJ]

I tried a search, but couldn't find anything special about this issue.

So, I have changed master and slave cylinders two weeks ago and workshop has installed a new clutch assy(Helix organic) with new fork(genuine Toyota part) and release bearing today. All the other gears work fine(because they are syncronised), but reverse crunches(because it isn't syncronised) now.

I have seen a thread/post about changing a longer slave cylinder rod or using a bushing, but couldn't find it again.

Could the reason for crunch be that the slave cylinder won't move the fork enough to get the clutch disengage fully? If I change a longer rod, how long it should be? Like 0.5cm longer or is that too much? Or will this even solve the problem?

Reverse was working silently before the car broke down.

Any comments/suggestions are welcome :-)

[StuDoc 72]

Adjust the rod behind the pedal this helps to disengage the clutch slight or engage it more depending on how you adjust it. You will want to be adjusting it so that the pedal sits slightly higher. This will cause the effect of the pedal being slightly pressed before you even touch it.

[JayJ]

Sorry, forgot to mention that pedal adjustment is done

[micky boy]

If all other gears are fine then it will have nothing to do with the fork!!! as the other gears would have trubble going in aswell

[StuDoc 72]

This is a wierd issue because when engaging reverse a car should always be completely stationary and by disengaging the clutch it would also cause the gearbox to come to a stop aswell. As is probably quite obvious the crunch is caused by when gears are moving and colliding with each other.

So this does make me think it is an issue with your clutch or cylinders causing the clutch not to disengage fully therefore there is still movement inside the gearbox when you select reverse hence the crunch. For anyone else asking the reason it does not happen on any other gears is because they are syncro'd and designed to be engaged while there is movement in the box.

1: Did you change the complete clutch or just the friction plate? (If so the pressure plate may be weak and unable to fully disengage the clutch)

2: Did you change the cylinders before changing the clutch and are therefore sure that the cylinders are working properly?

3: Why did you change the fork out of curiosity? It is not a part that tends to be effect by wear and tear as it is in an inanimate piece of metal and the smallest difference in angle between the old and new would cause this (Although the least unlikely)

[JayJ]

I have now picked up my car from the workshop and reverse is silent, I don't know why mechanic told on phone that the reverse is crunching.

And yes as StuDoc said, other gears are syncro'd so they will work fine even if there is a little movement in box, but reverse will remind you of it immediately.

1. Complete clutch was changed, friction plate and pressure plate both brand new.

2. Clutch biting point was changing randomly and then clutch stopped disengaging completely, so I though that the cylinders weren't working properly. At this point I'm almost 100% sure, that changing the cylinders were wasted time and money.

3. My car stood still 1½ months, while I tried to solve my clutch problem and was waiting the parts to arrive. So I decided to order the fork just to be sure, that all the parts are available when box is taken out. I knew that the fork was unlikely to be the problem, but I didn't want to take that risk and wait another two weeks, if it was broken for some reason :-)

So let's see if it starts crunching, but so far so good

[StuDoc 72]

Ideal buddy hope its ok now. Out of interest where did you get the cylinders from and how much did they cost?

Edited October 16, 2012 by StuDoc 72

[JayJ]

From Idrees / ID-Workz, 130 or something delivered, so good price ;-)