Gearbox shifting issues.

Car stuff Sep 1, 2020

With the repairs for the MOT 2020, Michael and I already replaced the gearbox oil. This made shifting a lot better, but definitely not near to what it should be.  

To give you an idea of what it's like to switch gears:

  • Gears won't engage properly most of the time, especially reverse, 1st and 2nd.
  • Gears pop out occassionally, this while the gearbox sings the song of it's people.
  • Gears suddenly engage as if there's no problem at all
  • In some positions the gear (let's say 1st) won't engage, but after driving a tiny bit in reverse or 2nd it will engage.  

Rather annoying to deal with all the time.

After some complaining online, describing my issues, someone told me to bleed the clutch.
Since it was indeed a hydraulic clutch, which used brake fluid, it did not seem like a bad idea to at least try it. If it was the issue, it's a quick fix. If it's not, then at least the clutch slave cylinder got some fresh fluids.  Nothing to lose there.  

The clutch slave cylinder, the part with the "S" line ending in the black plastic part
The clutch slave cylinder, the part with the "S" line ending in the black plastic part


I already replaced the brake fluid for the brakes only in March, but not the clutch itself.  
So on I went today, to renew the clutch brake fluid.  
All that's needed was a 12mm ring wrench, a bottle to catch the old fluid, and a hose to get it in to the bottle.  
And of course some new brake fluid, to replace the old dispelled fluid.  

The brake fluid I used for this job
The brake fluid I used for this job

The job

In order to renew and bleed the clutch slave cilinder, you need to do following steps:

  • Make sure the master brake cylinder is full
  • Make sure the master brake cylinder stays full
  • Take off the clutch slave cylinder bleeder valve rubber
  • Put the hose on the clutch slave cylinder bleeder valve
  • Put the other end in a bottle, I used a used water bottle for this
  • Crack the bleeder valve open
  • Push the clutch, check if brake fluid comes out through the hose
  • If okay, repeat this step 10 times.
  • Check master brake cylinder fluid level
  • Fill if necessary, repeat both steps until no more air or dirty fluid comes out
  • Close bleeder valve

and the rest is the reverse of the previous steps.  

Some pictures to give these steps somewhat to compare to:

Bottle and hose for the old fluid
Bottle and hose for the old fluid
Hose and wrench on the bleed valve, fluid is dark green but should look like apple juice
Hose and wrench on the bleed valve, fluid is dark green but should look like apple juice
Above the white cirlce: a lot of tiny bubbles, air that got pushed out the clutch slave cylinder
Above the white cirlce: a lot of tiny bubbles, air that got pushed out the clutch slave cylinder
Another angle of the bubbles
Another angle of the bubbles
Overview picture including wrench
Overview picture including wrench

Sadly when I removed the hose, I got to encounter something called "capillary action", a situation where fluid can leave the container even opposing gravity.  
So everything was full of brake fluid.  This is not an issue for metal parts, but definitely for paint.  
After a few minutes of hard scrubbing with not the right tools, everything seemed fine from what I could see.  
I still decided to go to the car wash, to do a underside wash.  

Next time the car is jacked up, I'll have to inspect the paint in and around the engine bay for potential brake fluid damage.  
It's a hassle, but stuff like this happens. ¯\_(ツ)_/¯    

Even with the brake fluid getting everywhere, it was worth the job.  
A three point turn is not annoying anymore, switching directions is totally doable.  
Gears pop into their place, only occassionaly it's not how it should be.  
But that's due worn synchronizer rings, except for a rebuild or rev-matching not really a thing I can do anything about anytime soon.  

All in all a very positive experience, and I'm happy about doing it.

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