Thank you! I watched all 17 of the videos. YouTube has come a long way since this video was made. This video is exactly what I needed to see. It all makes sense now. Worst case scenario in DIY is having to replace the whole drive shaft if you couldn't get the U-Joints out and in. I'm sure this guy makes it look easier than it would be for me. I would think the centering part would need to be more precise but I guess the clips keep it close enough to center to work. Did he say why he rotated the clips?

 

the hardest part about doing the job is making sure the needle bearings don't fall out when capturing the joint. i always hold the joint up against the cups while pressing the cups into place.

 

What a strange coincidence. The "Rockford Files" guy did a TV commercial for the RX-7. I'm going to go under the car and stare at it for a while, look at the nuts and bolts etc... maybe work up the courage to DIY . . . or not.

 

My neighbor is mechanical and I told him the story about the driveshaft a couple of days ago. He let me borrow a pair of jack stands and said he would be willing to help with the repair. The next day I was under the car staring at the driveshaft when he showed up with goggles, gloves and some tools. That's all it took to push me over the edge. It only took a few minutes to disconnect the back half of the muffler and loosen the shroud. I left one bolt in the shroud towards the front as it just needed to flex down enough to let the driveshaft out. We had a bit of trouble stretching the rubber muffler fasteners around their hooks but we did it. The two bolts holding the muffler on in the front of the car didn’t have to be removed.

I had to pull and release the E-Brake several times to lock and turn the driveshaft. This was the dangerous part as the car can roll off its jacks. After we removed the four bolts holding the driveshaft in place. Neighbor man pushed down on the tail pipe creating enough of a gap for me to slide the driveshaft out the back. I should have known but to my surprise a bunch of transmission fluid dripped out of the hole where the driveshaft was removed.

We slathered the U-joints with penetrating oil and hammered them for quite a while but they wouldn’t come out. Eventually I figured out that removing the dust rings on the inside of the yoke makes enough room to push the caps in through the holes where they can be split and removed. Once the caps are removed the U-Joint can be removed. I had watched a video where the caps are pushed out instead of in but I didn’t have that tool.

I used a stone drill bit attachment to smooth out the stake burs on outer edges of the yoke. I think they’re smooth enough now to push the new caps through. There is a bit of damage on one side of the driveshaft’s yoke. The defective U-Joint gouged a grove and caused some damage to the yoke. I plan to fill the gouge with epoxy putty to restore its shape so it will hold the cap in place. My neighbor supplied some Devcon 10110 for the job. I’ll have to clean, fill, file the putty into shape. The yoke probably doesn’t need putty but in case it does, the putty should keep the cap from moving in the yoke.

The new U-Joints will be here on the 7th I’ll need to grease them during install. What is the best grease to use? And what transmission fluid should I use?

 

i prefer synchromesh for the trans fluid:

Pennzoil Synchromesh Transmission Fluid 1 Quart

as far as grease, it's not super important, any old grease pump wheel bearing grease will do. i'm not sure if you can get some redline in a grease tube or not, unlikely locally.

 

The U~Joints arrived. I marked the ends of the driveshaft so I could put everything together the same way to preserve the balance. I pressed the caps in with a large C~Clamp. They would only go in until they were flush with the yoke so I used one of the caps from the old U~Joint to push the new caps in far enough to insert their clips. I squirted grease into the U-Joints until it was forced out of it’s middle. How many miles until they'll need grease again?

I used a piece of 2x4 as a lever to push the muffler down while I inserted the driveshaft. I didn't want to push the muffler down too much so it was a tight fit. The driveshaft eventually slid back in but I scratched some of the paint off of it doing that. Does it need special heat resistant paint? Or should I just cover it with some grease?

I put all the bolts back in and was ready to put the car on the ground. I had the cars passenger tires on the ground while the drivers side was held up with two jack stands. I used cinder blocks and scraps of wood to move the car up and down with a scissors jack. I found out this jack wasn't strong enough to lift the car from the middle by breaking two of them. Both times the car only fell a couple of inches onto the blocks. I think these jacks are made to lift a corner of the a car, not the whole side. Just then neighbor man showed up. He had extra jacks and we brought the car down, went for a ride, brought the car up to 30MPH and that nasty vibration was gone! The car did feel and sound a bit different, maybe things are adjusting, maybe it’s low on transmission fluid, probably both.

I bought two new scissors jacks rated for two tons each, three quarts of transmission oil and since I’ll be down there, I got two quarts of differential oil too. There will be heavy rain for the next few days, after that, I’ll put the oils in and bring it up to speed to see how it reacts.

I drained the transmission oil overnight. The oil was dark black, about two quarts of it came out so maybe a half quart leaked when I took out the driveshaft. The next day I pumped the new oil in and took it for a test drive. In about a half hour I could feel an increased smoothness. I drove it a little harder this time to test the U-Joints and the car remains free of vibration. I didn't have the right socket adapter but I was able to use an adjustable wrench on the two plugs. I’m not happy with the pump I bought for this, it took a lot of pumping for the 2.5 quarts and the pump didn't screw onto the bottle as I thought it would but it did work.

I found this video helpful for the oils.

The supplies:

The U~Joints
https://driveshaftparts.com/430-10A?search=uj430-10a

The grease

The grease gun.

The fluid pump:
https://oreillyauto.com/detail/c/performance-tool/performance-tool-fluid-pump/pfm0/w1139/v/a/8603/automotive-car-1988-mazda-rx-7?q=fluid+pump

Three quarts of Red Line 50304 for the transmission.
https://oreillyauto.com/detail/c/red-line-synthetic-oil/red-line-gear-oil-gl-4-75w-90-1-quart/rl00/50304/v/a/8603/automotive-car-1988-mazda-rx-7?q=red+line+mt-90

Two quarts of Red Line 57904 differential fluid.
https://oreillyauto.com/detail/c/red-line-synthetic-oil/red-line-synthetic-gear-oil-gl-5-75w-90-1-quart/rl00/57904/v/a/8603/automotive-car-1988-mazda-rx-7?q=Red+Line+57904

The Jacks

I’ll do the differential oil and the engine oil when the rain stops.