80 side shift clutch not disengaging. 2wd 20r
07-12-2018, 10:40 AM
#1
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80 side shift clutch not disengaging. 2wd 20r
This may go under right wrong or otherwise. Grandsons pickup. In my garage for weeks.
Clutch went out, 1980 20r side shift 4 speed 2wd. Replaced the clutch disc, pressure plate, throw out -release- bearing, pilot bearing. The bread thing worked great to get that out.
Last year new clutch master and slave cylinder. The pedal is the only thing adjustable.
It went all back together, no parts left over. The clutch would not disengage. Bled the cylinder a lot. It was moving. Tried lots of things no luck. Bled some more.
Adjusted the pedal way up and it showed some signs of life but was still not disengaging fully. After some tests and cussing.
We installed a 1/4" drive socket, 9/32 in size with a 1/4" Male Hex Drive to 1/4" Male Square Drive adapter in it. Ground down and rounded to fit in the clutch fork divot.
This slipped right over the slave cylinder rod and is held in by the clutch fork/ cylinder pressure only.
This worked, we lowered the pedal back to where the clutch engagement felt good, even with the brake pedal. So far so good.
Not so sure this is a good deal for the long haul but it is out of my garage and we will see how it holds up.
I know, the worst thing about this is using a standard socket, not metric but the 8 felt too big and the 7 was too small.
Clutch went out, 1980 20r side shift 4 speed 2wd. Replaced the clutch disc, pressure plate, throw out -release- bearing, pilot bearing. The bread thing worked great to get that out.
Last year new clutch master and slave cylinder. The pedal is the only thing adjustable.
It went all back together, no parts left over. The clutch would not disengage. Bled the cylinder a lot. It was moving. Tried lots of things no luck. Bled some more.
Adjusted the pedal way up and it showed some signs of life but was still not disengaging fully. After some tests and cussing.
We installed a 1/4" drive socket, 9/32 in size with a 1/4" Male Hex Drive to 1/4" Male Square Drive adapter in it. Ground down and rounded to fit in the clutch fork divot.
This slipped right over the slave cylinder rod and is held in by the clutch fork/ cylinder pressure only.
This worked, we lowered the pedal back to where the clutch engagement felt good, even with the brake pedal. So far so good.
Not so sure this is a good deal for the long haul but it is out of my garage and we will see how it holds up.
I know, the worst thing about this is using a standard socket, not metric but the 8 felt too big and the 7 was too small.
07-14-2018, 02:35 PM
#2
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I don't know if the '80 4 speed is similar or not, but I have a '78 5 speed & would assume that the hydraulics are similar if not identical. I also just did a complete clutch system job so have a few suggestions. Questions:
1. When you bled the system are you sure you got all the air out? (Sorry, have to ask) How does the clutch pedal feel, any mush at all or is it very firm?
1A. Did you only open or close the bleeder screw with the pedal being held all the way to the floor? If you don't do this, it's impossible to bleed the system correctly.
2. Does your slave cylinder have a "plain" rod, or is part of it threaded, with what looks like an acorn nut & a regular nut on it? The '80 2WD slave cylinder should have the "plain" rod. It should look like this:
3. You say your clutch fork has a "divot"; not a six sided hole in it? It's solid?
I'm asking all this to find out if something was swapped by a previous owner. The stock stuff for the truck should be clutch fork end solid with divot & "plain" slave cylinder rod; not adjustable.
4. Did you check the master cylinder pushrod freeplay? This is how much the pedal moves before it actually starts to push the rod. It should be 1/4" or less (spec 0.20").
Pedal height spec should be slightly over 6 inches (6.0825", by the book).
Hope this helps.
1. When you bled the system are you sure you got all the air out? (Sorry, have to ask) How does the clutch pedal feel, any mush at all or is it very firm?
1A. Did you only open or close the bleeder screw with the pedal being held all the way to the floor? If you don't do this, it's impossible to bleed the system correctly.
2. Does your slave cylinder have a "plain" rod, or is part of it threaded, with what looks like an acorn nut & a regular nut on it? The '80 2WD slave cylinder should have the "plain" rod. It should look like this:
3. You say your clutch fork has a "divot"; not a six sided hole in it? It's solid?
I'm asking all this to find out if something was swapped by a previous owner. The stock stuff for the truck should be clutch fork end solid with divot & "plain" slave cylinder rod; not adjustable.
4. Did you check the master cylinder pushrod freeplay? This is how much the pedal moves before it actually starts to push the rod. It should be 1/4" or less (spec 0.20").
Pedal height spec should be slightly over 6 inches (6.0825", by the book).
Hope this helps.
07-16-2018, 07:14 AM
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1. We bled this over 2 afternoons. I tried vacuum bleeding, gravity bleeding and as you said only "open bleeder when depressed" with the a hose from the bleeder to a jug with fluid.
We put almost a full large jug of brake fluid through it is a number of ways. Of course it is possible there is still air in there. I feel like we had the best results using the "open bleeder while depressed" method. The pedal is firm and the same pretty much through its full travel. It looked like it should be moving enough but the clutch was not releasing.
We raised the rear tires, started in 4th gear and tried the brakes. It just would not even try to release or even slip.
The cylinder was moving the fork most of the time we were bleeding it. We finally tried to assist the fork with a pry bar to get it to move farther. We couldn't move it farther which I thought was odd. I was expecting it to move back a bit more and release. I guess we didn't get the right leverage. We had no luck with this.
We were to the point of taking it apart again. We raised the pedal from under the dash as a last ditch and then went to adding the spacer and it was instantly good.
But it was perfect once we took it off the jacks and with the wheels on the ground.
2. our slave and rod looks exactly like your photo.
3. the fork is solid no hole where the slave meets the fork. Just a divot. This is why we put the hex to square adapter in the socket, to make a round taper to fit the divot.
4. we did not check the push rod play distance. Once we added the spacer, the pedal was still set way high and the disengagement was way at the top of the pedal movement.
We adjusted the pedal down below the brake pedal height and the disengage was all the way at the floor. We put the pedal back even with the brake and it felt like a good spot.
It is working better than ever, so I have heard. Thanks for the pointers and input. Roy.
We put almost a full large jug of brake fluid through it is a number of ways. Of course it is possible there is still air in there. I feel like we had the best results using the "open bleeder while depressed" method. The pedal is firm and the same pretty much through its full travel. It looked like it should be moving enough but the clutch was not releasing.
We raised the rear tires, started in 4th gear and tried the brakes. It just would not even try to release or even slip.
The cylinder was moving the fork most of the time we were bleeding it. We finally tried to assist the fork with a pry bar to get it to move farther. We couldn't move it farther which I thought was odd. I was expecting it to move back a bit more and release. I guess we didn't get the right leverage. We had no luck with this.
We were to the point of taking it apart again. We raised the pedal from under the dash as a last ditch and then went to adding the spacer and it was instantly good.
But it was perfect once we took it off the jacks and with the wheels on the ground.
2. our slave and rod looks exactly like your photo.
3. the fork is solid no hole where the slave meets the fork. Just a divot. This is why we put the hex to square adapter in the socket, to make a round taper to fit the divot.
4. we did not check the push rod play distance. Once we added the spacer, the pedal was still set way high and the disengagement was way at the top of the pedal movement.
We adjusted the pedal down below the brake pedal height and the disengage was all the way at the floor. We put the pedal back even with the brake and it felt like a good spot.
It is working better than ever, so I have heard. Thanks for the pointers and input. Roy.
07-18-2018, 06:35 AM
#4
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Always trying to help if I can, no problem.
1. I also had the best results with the "open bleeder when depressed". This has to do with a check valve within the master. If you've got a firm pedal I would think you don't have any air in the system. As for trying to use the pry bar to assist in moving the clutch fork, it's nearly impossible to do so. My understanding is that it takes at least 500 pounds of pressure to move the pressure plate spring fingers. Unless you're the Incredible Hulk you aren't gonna move that fork on your own, even with a huge-mongous pry bar. :^) You may already know the rest of this but want to post it here for anyone else that comes along who may not know. The hydraulic system can move it because it acts as a force multiplier. Has to do with the ratio of pedal travel (large/about 6") to pressure plate spring finger travel (small/about 3/4"). That's a 7.5 to 1 advantage. Doing the math it only takes about 60 pounds pressure on the clutch pedal to get that 500 pounds pressure on the other end. You did the right thing in raising the pedal; it gave you more leverage.
2. Hoped so, at least we know you have the right parts.
3. Again, correct part. Batting a 1000 on parts at least!
4. From what I've seen the clutch & brake pedal being even with each other is correct for these trucks. Your report of it working well confirms that.
Nice job on the modification to solve a problem. Nice to know that good old fashioned garage engineering isn't dead either. Good work sir & nice job keeping 1 more of these trucks useful & on the road.
1. I also had the best results with the "open bleeder when depressed". This has to do with a check valve within the master. If you've got a firm pedal I would think you don't have any air in the system. As for trying to use the pry bar to assist in moving the clutch fork, it's nearly impossible to do so. My understanding is that it takes at least 500 pounds of pressure to move the pressure plate spring fingers. Unless you're the Incredible Hulk you aren't gonna move that fork on your own, even with a huge-mongous pry bar. :^) You may already know the rest of this but want to post it here for anyone else that comes along who may not know. The hydraulic system can move it because it acts as a force multiplier. Has to do with the ratio of pedal travel (large/about 6") to pressure plate spring finger travel (small/about 3/4"). That's a 7.5 to 1 advantage. Doing the math it only takes about 60 pounds pressure on the clutch pedal to get that 500 pounds pressure on the other end. You did the right thing in raising the pedal; it gave you more leverage.
2. Hoped so, at least we know you have the right parts.
3. Again, correct part. Batting a 1000 on parts at least!
4. From what I've seen the clutch & brake pedal being even with each other is correct for these trucks. Your report of it working well confirms that.
Nice job on the modification to solve a problem. Nice to know that good old fashioned garage engineering isn't dead either. Good work sir & nice job keeping 1 more of these trucks useful & on the road.
07-19-2018, 06:01 AM
#5
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If the slave and rod look exactly like the photo, you have the wrong part. The slave for the trans you have has a longer rod, threaded with adjuster.The one on the pic is for 81 and newer.
07-19-2018, 05:11 PM
#6
Registered User
It is the correct part for the 1980 2 wheel drive trucks. The one with the threaded rod and adjuster nut is for 1980 4 wheel drive only. Check any parts catalog you like and it's specified. I did.
07-20-2018, 08:15 AM
#7
Registered User
I just pulled one off a 80 Toyota 2wd 4 speed, and one off a 73 hilux that had a 2wd 80 5 speed swapped in. This isn't by parts lookup, this is by owning a lot of Toyotas through-out the years, most to be parted out.
But anyways....have you tried bench bleeding the master cylinder? Also, check to make sure the whole clutch assembly inside the cab is not broke away from the bottom of the cowl area. when this happens, the clutch assembly is rotating when the pedal is depressed, limiting the amount of pedal throw. Adding spacers to something that didn't have them before is masking an issue.
But anyways....have you tried bench bleeding the master cylinder? Also, check to make sure the whole clutch assembly inside the cab is not broke away from the bottom of the cowl area. when this happens, the clutch assembly is rotating when the pedal is depressed, limiting the amount of pedal throw. Adding spacers to something that didn't have them before is masking an issue.
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