Grinding First Gear!

[Rineheitzgabot]

My '69 SIIA needs the slave cylinder rebuilt (I can tell this by the fact that, periodically, the whole hydraulic circuit needs topped off with fluid). I will get to this repair in the next week or so, but I am not sure if it is causing the following problem and the reason for this post: When I go to shift from neutral to first, at a complete stop, it will not go without grinding, and some extra force. My feeling is, that the slave cylinder, even when bled, and in normal "working" order, aside from the leak, is losing pressure at the end of the stroke, not disengaging the clutch enough (even with the pedal all the way to the floor). It is fairly faint (the grinding). I have tried adjusting the clutch to give the whole motion a little more stroke/throw, and it still does it. When rolling up to a stop, it will go into gear with no grinding or extra force if you catch it at just-the-right-moment before the vehicle comes to a complete stop.

One thing that keeps me believing that it is the slave cylinder, is the fact that it will not do it at all when it is cold. I think that maybe the viscosity of the fluid is thicker and creates more pressure when cold, and gives the clutch enough umph at the end of the stroke to disengage it.

I have a deep-seated worry that it is in the transmission somehow. Please ease my mind! I would love to get some input on this dude.

[galen211]

Have you tried pumping the clutch before putting it into gear? Just like a brake pump it a few times to build up pressure.

[Rineheitzgabot]

I have tried pumping the clutch, but it does not change. Unless it would need pumped more than twenty times.

Thanks.

[Rusty and Tad]

Have you tried double clutching?

[pbmonk]

When the clutch is OK you can avoid grinding by putting it in third first and then in first (I'm talking about when at a standstill).

Maybe the problem is with the linkage or bronze bushes below the slave cylinder. There is a sleeve and 2 pin thing that connects the clutch actuator to the shaft right close to the gearbox. This can wear. Also the shaft can wear in the bronze bushes due to lack of lubrication. Or the shaft can seize solid in the bushes so that the entire bush rotates in its holder making the clutch very heavy. Any slop in the linkage could be a problem perhaps.

Of course this sounds unlikely if the temperature is a factor. So I guess I am just rambling.

Peter

[Rusty and Tad]

Peter,

I had forgotten about that trick - shifting to 3rd then 1st. One of my vehicles, and I can't remember which for the life of me, I had to do that. I think it may have been a VW Westfalia... or the Dodge truck... or maybe the school bus I drove so many years ago... Anyway, it always worked but I have no idea why. And if I recall right all I had to do was touch third and it would go into first without the grind.

[Rineheitzgabot]

Even though I would like to get to the root of the problem (assuming that is possible), The third-then-first routine works great; not once did it grind on an hour drive I took last night.

Thanks!

[Tom109]

Peter's trick is a good one. You don't actually have to go "into" 3rd, just touch it enough to get the synro to spin, then go right into 1st.

If you are going to rebuild the slave, my suggestion is to replace it with new, along with a new flex line. If you have your heart set on rebuilding it, do so, but pack it with red brake grease and put it in your spares kit.

Less headaches and more time for the sampling das Reinheitsgabot's finest!

Tom P.

[Rineheitzgabot]

In the year 1516...

That's another story.

Tom, obviously a consumer of the fruits of the laborious science of zymurgy (or maybe a zymurgist himself), is also, a knowledgable LR techy. I believe I will follow your advice, the entire cylinder doesn't cost that much, and I imagine this solution to be more effective.

Thanks,
Gary

ps: Not many people know of the German purity law, and the fact that I have obscured the spelling a bit makes it look more like an austrailian musical instrument than a doctrine.

[oscar]

Had the same problem. Took the slave cylinder apart, cleaned it and put it back together. Everything cool now. I think that due to gravity the dirt in that system ends up where it gets in the way the most.