We are UK based, and our 17 year old son took our 1929 Phaeton down to the South of France earlier this summer. An 1800 mile round trip. On the return journey, the clutch plate ripped its centre out. Luckily this happened in a town, and a passing welder was able to weld it back together again, and they got home safely.
The centre splines were very heavily worn, which indicates the clutch plate had been moving in the flywheel. It had not been in there that long - say a couple of years. We have no reason to believe that the pressure plate is behaving anything other than it should. There was no clutch slip etc. until the centre ripped out and then it was full stop.
There is a pilot oiled bronze bearing set into the crankshaft, and we are now investigating to see if that has worn to allow the plate to move. Does anyone else have experience of this?
If it is worn, we can machine up another. The tech manuals do not say how to get it out (it is pressed in), and we are a bit reticent to launch a large drill into the centre of the crank to remove it. Does anyone have tips or tricks to get it out, and what modern material is now used when replacing please?
We have thought that it could all have been misaligned when it was rebuilt two years ago. We passed this work out then, so did not fully see what happened. Does anyone have any other thoughts as to what might have caused the centre to rip out. It could always have been a duff plate!
We have a relined spare original Chev plate, so are just about to drop the gearbox again to do a lasting repair. My son has become an expert at its removal having done it three times on the roadside in France!
Images of the plate and the fettle below. Thanks in advance for any input
To remove the bushing pack some grease inside and then using a shaft of the correct diameter heavily strike the shaft . It should apply enough pressure to unseat the bushing and force it out.
Hello GNspeedfreak, m006840 advised correctly about the pilot bushing removal. It uses hydraulic pressure of the grease forced forward to push bushing rearward for removal. The key is using a shaft of close tolerance so as not to allow grease to just squeeze out around the shaft and splatter your eyes and face. A youtube video showed using pieces of sandwich bread being stuffed and packed into the pilot hole to do the same work instead of using grease. It works, just keep stuffing and pounding. Now, there are puller tools made for this job using fingers that expand to grip bushing and slide hammer bushing out. The picture of the clutch plate appears to show four separate sheet metal plates that were sheared off from the spline shaft. My guess: stress cracks and corrosion and failure. If you believe that the transmission input shaft may be central to the failure, check all splines for wear and also the transmission input bearing and retainer.
If I remember right, a steel bell housing was used in 1929, rather than cast iron. They can and do get distorted, creating alignment issues as you suspect.
To check: With the flywheel and clutch removed, and the bell housing on the engine, mount a dial gauge to the flywheel and rest the gauge pointer on the INNER edge of the round hole in the bell housing that the transmission mounts in. Rotate the crankshaft and watch the needle on the dial gauge to check for run-out or misalignment.
Misalignment in this area would certainly cause premature wear of the splines in the clutch plate and possibly crack the center out of the plate
A quick update on this project. We now have the gearbox out. The bronze bush in the crank did not want to budge. We used grease and bread. The grease got very hot under the hydraulic pressure and the bread was not nearly as good as the grease, but neither would move the bush despite a very close fitting bar that we were hammering in.
In the end my son tapped the bush with a 1/2 inch tap and drove the bush out using a half inch bolt. This worked well and did not damage the crank.
We are now turning up a new bush in phosphor bronze. We think the old clutch was made of cheese when compared to the genuine Chev. clutch plate that is going back in.
