Sunday 6 February 2022

E30 318i: Replacing Clutch Slave-Cylinder - Quick + dirty guide!

Clutch reservoir suddenly low on fluid? Gearbox housing covered in it? Sounds like a popped slave-cylinder. Not to worry, this has to be one of the easiest to replace ever made!

* This guide covers the M40 engine and 5-speed gearbox, but process is the same for most models. *

1. Lift the left side of the car.

2. Remove the 13mm nut from the outer side of the slave-cylinder. This one is easy to access and can be got with a ring-spanner or socket, but the ratchet is quite snug to the gearbox.

3. Remove the 13mm nut from the inner side of the slave-cylinder. This is quite difficult to get to as it is inhibited by the clutch-hose as well as limited access in the trans.-tunnel. I managed it with a socket and a 4" extension bar to get past the hose/pipe. 

* I have seen someone getting that difficult to reach nut using a longer extension bar and the ratchet further back behind the gearbox, but this was not possible on my E30, so I'm guessing this may be for 4-speed boxes or older M10/M20 engines. If yours cannot be got with the details in step 3, then try this. *

4. Remove the slave-cylinder fr the gearbox and allow to hang down on the hose.

5. Clamp the hose (optional, but saves time when bleeding system later).

6. Remove the hose end from the slave-cylinder using an 11mm wrench so the old unit can be discarded. [It is much easier to grip the slave-cyl. by hand while it is removed from the gearbox and get a turn on the pipe-collar, as well as minimising leaks from the hose.]

7. Prime the new slave-cylinder by removing the bleed-nipple and carefully pouring DOT4 brake/clutch fluid into the hole at the top for the hose/pipe until the air is displaced and the fluid run out of the lower hole. It won't need much. Refit and tighten the bleed-nipple. 

8. Refit the hose-end to the slave-cylinder and remove the hose-clamp if you're using one.

9. Refit the slave-cylinder to the gearbox and tighten the two 13mm nuts.

10. Top up the clutch reservoir with DOT4 brake/clutch fluid and bleed the system of air. [Which bleeding technique you use is up to you, but for all BMW clutches I would recommend using a one-way valve attached to the bleed nipple as detailed in THIS POST, which saves time and headaches.]

E30 316i / 318i Electrical Troubleshooting Manual [1984 onwards] - PDF 8.9MB


  1. Index
  2. How to Use this Manual
  3. Symbols
  4. Wire Size Conversion Chart
  5. Systematic Troubleshooting
  6. Diagnostic Connector
  7. Power Distribution Box
  8. Fuse Data
  9. Schematic Diagrams
  10. Component Charts and Figures

Friday 4 February 2022

Mini ONE 1.4d: Bubbling from radiator bottle... is it the cylinder head?


So today we have a MINI ONE 1.4 diesel and guess what... it's overheating! Coolant is being lost somewhere and we find that it is bubbling out of the header-tank. My first guess in this situation is the head-gasket, but for a cheap fix (possibly, but better than going straight to ripping a friend's car apart) we tried a new radiator / header-tank cap, which was fitted yesterday and, although it has reduced the bubbling problem, there is still some coming out when the engine is warm, coolant lost and the temp. needle creeping up. 
This week the poor running has begun... occasional juddering, drop in revs and the odd misfire noise. Hmm... I have said to keep using it until the running becomes unmanageable (provided it's kept watered and is not overheating of course!) and am hoping for a weekend of better weather so I can have a proper look round it and, if need be, open it up. Watch this space.

EDIT: With not many tell tale signs of the head gasket being blown, someone has kindly suggested that the water pump is failing and not circulating coolant properly, so here's something else to look into. Yay!

E30 318i: Water in rear footwell - windscreen cowl leaking? Koi carp anyone??

After heavy rain I noticed the rear passenger foot well in the E30 is full of water. Can't see any signs of water ingress through the door seals or any stains in the headlining, but am told a common cause of this is the windscreen-cowl, so will be looking into this soon. For now, I have drilled a nice drain hole so at least it won't be filling up again.