Increase stroke length of master cylinder?
Discussion
Due to parts availability I’ve had to replace my clutch master cylinder with an almost-right part, slave replaced at the same time. Hydraulics working, clutch fork can be observed moving (but not much).
Back in the car, the pedal is sitting low. Has a nice fluid-ey feel to it, no sponge, but very limited travel. Returns to a point about halfway up then stops firm, no further travel. I believe that I’ve cocked up and although the pistons appeared to be the same length to the eye, me new one is actually shorter. Am I right in thinking this would explain the shorter return length and limited stroke, because although it’s working the cylinder is too far away / piston rod is too short and it’s at full extension before the pedal has returned all the way? Needless to say that I do not have enough travel on my new short throw clutch pedal to actually disengage the clutch.
If that is the case, has anyone ever bodged an extension onto the piston rod on a master cylinder? As long as it stays within its orientation I can’t see a problem with it, I’m just effectively increasing the rod length. I’m thinking a rod end with the hole for the pin, with a bolt securing it to the current pin hole and some form of bracing to keep it in line.
Is this a daft idea, it seems like an easy solution to me and I’m interested if anyone has tried something to this effect?
Back in the car, the pedal is sitting low. Has a nice fluid-ey feel to it, no sponge, but very limited travel. Returns to a point about halfway up then stops firm, no further travel. I believe that I’ve cocked up and although the pistons appeared to be the same length to the eye, me new one is actually shorter. Am I right in thinking this would explain the shorter return length and limited stroke, because although it’s working the cylinder is too far away / piston rod is too short and it’s at full extension before the pedal has returned all the way? Needless to say that I do not have enough travel on my new short throw clutch pedal to actually disengage the clutch.
If that is the case, has anyone ever bodged an extension onto the piston rod on a master cylinder? As long as it stays within its orientation I can’t see a problem with it, I’m just effectively increasing the rod length. I’m thinking a rod end with the hole for the pin, with a bolt securing it to the current pin hole and some form of bracing to keep it in line.
Is this a daft idea, it seems like an easy solution to me and I’m interested if anyone has tried something to this effect?
You need to know whether the master cylinder piston is actually returning to the normal at-rest position at the end of its travel.
I think you'll find it isn't. In that case you have a problem that needs fixing and lengthing the pushrod etc won't fix it.
Does the clutch pedal have a return spring?
I think you'll find it isn't. In that case you have a problem that needs fixing and lengthing the pushrod etc won't fix it.
Does the clutch pedal have a return spring?
GreenV8S said:
You need to know whether the master cylinder piston is actually returning to the normal at-rest position at the end of its travel.
I think you'll find it isn't. In that case you have a problem that needs fixing and lengthing the pushrod etc won't fix it.
Does the clutch pedal have a return spring?
No return spring on the clutch. Is there any reason why the master cylinder wouldn’t fully return? It’s a brand new part and FWIW the pedal does provide good resistance over the small amount of travel it has.I think you'll find it isn't. In that case you have a problem that needs fixing and lengthing the pushrod etc won't fix it.
Does the clutch pedal have a return spring?
CanoeSniffer said:
No return spring on the clutch. Is there any reason why the master cylinder wouldn’t fully return? It’s a brand new part and FWIW the pedal does provide good resistance over the small amount of travel it has.
On the ones I've seen, the piston seal is a directional cup seal. If you pull the pushrod out, fluid will flow past the seal into the circuit. Won't the piston pull back by hand? Normally the pedal mechanism incorporates an overcenter spring which pulls the pedal back.If not, I think you'll need to take the m/c off and check the length of the pushrod at both ends of its travel and compare with the old one. Seems unlikely they'd be different and I'd have thought any difference would be obvious with the two parts on the bench.
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