An open forum for all enthusiasts of the classic 60 series Nissan Datsun Patrol to gather and share information and gain knowledge. Members share off-road stories, restoration advice, modification ideas in an atmosphere free of a single controller. The fo
Won't run? Engine, cooling system, fuel pump, carb, clutch, tranny, brakes, etc. The old messages from the NPCA 'Engine & Mechanical' category are here.
Well I believe in abundance meaning it’s possible to have only good things happen. Yesterday started as one of those days. I sorted out the Webers on my Alfa and corrected a braking issue. Good news, time to get back on the 60 Patrol list.
Ut OH!, when I went to pull the Patrol back in the shop there was a sudden rotational banging noise coming from the engine compartment. It turns out something gave up in the bell housing. The clutch is always engaged. The clutch pedal feels normal (hydraulic system) and if starting the Patrol in neutral the engine is smooth and quiet (whew!). The clutch is not releasing as witnessed by turning the engine over in 1st gear and the Patrol moving forward.
I observed the slave cylinder when the clutch pedal is pushed and it moves normally. I pulled the pressure plate inspection cover expecting to find loose parts and nothing. Next step will be to push clutch pedal and observe to see if the throwout bearing moves. I can only see one of the pressure plate fingers and it looks in position.
Before I pull the transmission expecting a pressure plate failure any thoughts from someone experienced in the Patrol clutches and release mechanism is welcome.
Here’s a photo just before the failure
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One possibility is that the pilot bearing at the cranshaft is binding both the transmission and the engine. The noise you heard might point to that.
Why don’t you try to start the engine in 3rd gear. The transmission will pose the biggest resistance to the engine and the effort might free the pilot bushing. Just a wild idea I have at the moment.
Nice Patrol.
When you push the clutch pedal in you should be able to see (via the inspection cover) if the clutch plate moves a very small from the flywheel. If not then the throwout bearing and/or clutch plate are faulty.
But try what Esteban said first.
Not sure if I will get there.
Not sure if I will get back.
But I usually do!!!
On Monday I was able to observe the clutch while the pedal was pushed and released. All the components appear to be working correctly. The throwout bearing moves in against the fingers and they rotate and the pressure plate releases. So, I put the transfer case in low pushed in the clutch and started the engine. And everything works fine.
I’m guessing that the clutch plate must have adhered to the flywheel and it broke loose. I’ve seen that happen with metallic brake pads adhering to rotors and this seems similar. I’ll drive the Patrol around locally and make sure it’s reliable before venturing out too far.
This is an update with important information regarding clutch master cylinder replacement.
In this thread I previously stated that the banging noise had gone away and the clutch disc must have been stuck to the pressure plate. But, that was not the case.
Once again the clutch appeared to be engaged and unable to release. The banging noise started again and trying to start the Patrol in gear it would lurch forward and out of gear it would start, but made the banging noise.
So, here’s what I found and how I created this issue myself. One of my projects was to replace the Brake Master Cylinder with a dual reservoir for safety and replace the Clutch Master Cylinder due to age and to match the new Brake Master. It was the replacement of the Clutch Master Cylinder that caused my issue.
What I discovered was that the new Brake Master Cylinder (I got the part number of another post on 60Patrol) had too much capacity. The bore of the cylinder was 13/16” whereas the original was 5/8” bore. The extra capacity of the new cylinder created extra volume and therefore extra movement of the slave cylinder and throwout bearing. Actually, too far. I calculated that the volume increase is 41% more than the stock 5/8” cylinder!
So, when I pushed the clutch pedal all the way in it would force the pressure plate fingers into the clutch disc (spinning it) and engaging the transmission spline. Therefore when the clutch was supposed to be released it was actually engaged by the pressure plate hitting the clutch disc.
I was able to find a replacement Brake Master Cylinder with a 5/8” bore using a 1969 Datsun 512 pickup as the search and it looks like the original unit except it has the newer plastic reservoir. I did have to swap the plunger off the original part since the new plunger was adjustable and too long in the shortest position. The part number was CM1102 and I bought it was O’Reilly Auto Parts.
