DIYMAN
Senior Member
- Joined
- Dec 16, 2007
- Messages
- 421
- Reaction score
- 9
- Location
- Nr. Harrogate
- Your Mercedes
- E270cdi/53 plate/2.7l 5cyl.
Tools required: Pozi 2 screw driver, medium flat blade screwdriver, junior hack saw or angle grinder with 1mm disc. battery drill (or mains) with 6mm bit and ideally a 3mm bit 100mm long.
Materials required: New spring (details later), a 6BA screw and nut, grease and locktite.
1) Remove plastic top cover, one Pozi screw and plastic clips.
2) Remove big piece of the small broken spring, maybe hidden in the grease.
3) Move lock mech. into unlocked position using manual rod, then push back the metal arm into which the internal handle cable is hooked, hold the arm in this position some how, I jammed it with a large wood screw (see photo.)
4) Using a small hack saw or angle grinder, cut off the corner of the metal plate which is obscuring the top of the rivet that fixes the black plastic cam follower. I used a piece of damp kitchen towel to cover the lock mech. when cutting to catch the metal bits. Then used a small file to take the sharp edge of the cut.
5) Turn the lock over and locate the back of the hollow rivet the holds the cam follower, using the long 3mm drill bit, drill down the centre of the rivet until the hole is visible on the other side in the centre of the rivet head.
6) Now using the 6mm bit centred on the 3mm pilot hole, drill off the head of the rivet and recover the flat washer, don't drill too deep!!
7) The black cam follower must now be raised upwards on its plastic bearing, just enough to allow the tail of the broken spring to be removed and the new spring put in its place. It may be difficult to see the small hole into which the spring fits due to a covering of grease.
8) Push the cam follower back down onto its bearing and with the original washer placed under the head, insert the 6BA screw through the centre of the rivet, offer the nut up from the back and rotate the screw to draw the nut up into the remains of the hollow rivet. The nut will jam and become captive in the rivet, fully tighten the screw then back off 1/4 turn so the cam follower can turn on its bearing.
9) Remove the wood screw or what ever used to hold the metal arm back and let the arm return under its spring pressure.
10) Clean out any remaining bits of swarf using a magnet and screw driver then grease the moving parts before replacing the plastic cover on the lock, when replacing the cover take care to make sure the small spindles of the gear wheels enter the holes in underside of the cover.
11) Finally test the lock on the bench about 10 times, this can be done by inserting pieces of single strand telephone wire into the connector sockets of the red and black wires and applying 12 volts, reversing the polarity for lock and unlock.
Replacement springs, the first thing to note is that springs on the left side of the car are known as R/H springs and those for the right on the car are termed L/H due to the coil direction.
I was fortunate to obtain some sample springs, hand made by a spring manufacturer so I could investigate the possibility of repairing the locks, in-order to make it worthwhile setting up a machine to manufacture the springs they would need to see a demand for about 100 springs and they would probably cost between £1 and £2 each. They have produced similar car lock springs previously, for other than Mercedes owners clubs.
If an indi would like to take on a suppliers role for the springs I can pass their details on to the spring manufacturers.
Materials required: New spring (details later), a 6BA screw and nut, grease and locktite.
1) Remove plastic top cover, one Pozi screw and plastic clips.
2) Remove big piece of the small broken spring, maybe hidden in the grease.
3) Move lock mech. into unlocked position using manual rod, then push back the metal arm into which the internal handle cable is hooked, hold the arm in this position some how, I jammed it with a large wood screw (see photo.)
4) Using a small hack saw or angle grinder, cut off the corner of the metal plate which is obscuring the top of the rivet that fixes the black plastic cam follower. I used a piece of damp kitchen towel to cover the lock mech. when cutting to catch the metal bits. Then used a small file to take the sharp edge of the cut.
5) Turn the lock over and locate the back of the hollow rivet the holds the cam follower, using the long 3mm drill bit, drill down the centre of the rivet until the hole is visible on the other side in the centre of the rivet head.
6) Now using the 6mm bit centred on the 3mm pilot hole, drill off the head of the rivet and recover the flat washer, don't drill too deep!!
7) The black cam follower must now be raised upwards on its plastic bearing, just enough to allow the tail of the broken spring to be removed and the new spring put in its place. It may be difficult to see the small hole into which the spring fits due to a covering of grease.
8) Push the cam follower back down onto its bearing and with the original washer placed under the head, insert the 6BA screw through the centre of the rivet, offer the nut up from the back and rotate the screw to draw the nut up into the remains of the hollow rivet. The nut will jam and become captive in the rivet, fully tighten the screw then back off 1/4 turn so the cam follower can turn on its bearing.
9) Remove the wood screw or what ever used to hold the metal arm back and let the arm return under its spring pressure.
10) Clean out any remaining bits of swarf using a magnet and screw driver then grease the moving parts before replacing the plastic cover on the lock, when replacing the cover take care to make sure the small spindles of the gear wheels enter the holes in underside of the cover.
11) Finally test the lock on the bench about 10 times, this can be done by inserting pieces of single strand telephone wire into the connector sockets of the red and black wires and applying 12 volts, reversing the polarity for lock and unlock.
Replacement springs, the first thing to note is that springs on the left side of the car are known as R/H springs and those for the right on the car are termed L/H due to the coil direction.
I was fortunate to obtain some sample springs, hand made by a spring manufacturer so I could investigate the possibility of repairing the locks, in-order to make it worthwhile setting up a machine to manufacture the springs they would need to see a demand for about 100 springs and they would probably cost between £1 and £2 each. They have produced similar car lock springs previously, for other than Mercedes owners clubs.
If an indi would like to take on a suppliers role for the springs I can pass their details on to the spring manufacturers.
