Does the 89 BKO have a rear double u-joint, cv centering ball yoke Cardan knuckle with slip joint/yoke.....wonderful design....PITA......?
If so you need the small 5/16" ($4-5.00) socket for the front, 4 strange looking bolts heads that thread into the back of transfer case flange so becareful not to strip them or you're FAWKED....and for the yoke at the rear differential it's just a 1/2" wrench.
Both my drive shafts are slip yokes but you do need Mobil 1 synthetic grease which runs around $5-6.00 can BUT clean the slip shaft and inside the yoke and you'll see deep set groves, M/F and on the slip shaft only clean it down to the "blue teflon" stuff DO NOT clean that off so go easy then liberally regrease both, I used a long wooden dowel and paper towel to shove the synthetic grease down inside to the bottom of the yoke.
There several threads on the Cardan Knuckle and you need to know the "sequence" how to take it apart and put it back together correctly otherwsie it will turn into a nightmare, study up FIRST....if you have a 4" vice grip on a work bench you can rent a tool from O'Reillys basiclly for FREE if returned within 48 hours you just need to leave a refundable deposit OR Harbor Freight sells the "balljoint/u-joint" press for around $69.99 minus any internet coupon, 10-15% off. It's a great big industrial size C clamp you mount in the 4" vice grip using a 7/8 socket and long torque wrench for leverage, liberal amounts of PB Blaster pressing u-joint caps out and any oil for in gets the job done nicely.
The trick with the u-joint cap "pins" inside so you don't disturb or move them around while installing is to stick of gob of grease right inside, fill it up and when you put in the + center the grease will just ooze out, NBD...wipe and clean.
For the front drive shaft it's easier, remove the transfer case skid plate and have at it with 1/2" wrench on both ends.....don't forget to clean the slip joint "dust cover boots" inside and out, I washed mine in detergent and they came looking out like new, I used red tie-wraps instead of the PITA metal OEM clamp/s...your call.
In some case the cv centering ball yoke can be reubilt with a new seal, ball and spring form broncograveyard for around $12.00 plus shipping OR you'll need to buy one, $69.99 form O'Reillys which is what I had to do because my cv yoke was not rebuildable due to the way it's machined, doesn't come apart.
Once you rebuild both shafts you won't believe the difference when you pull away from a standing stop at a light.......NO MORE LAG, CLUNK...lol lol...and you feel the transmission shifts smoother..mine does.
Use the "search tool" and IIRC FSB member RickyB had thread with extra links on cleaning/greasing the slip joint along with some other FSB guys rebuilding the Cardan.....I've got over 500 saved posts and need to learn hot to copy the link thing....sorry!
Just take your time and be patient and "listen for plink sound" when pressing a u-joint "cap" in passed the lock spring/clip "grove" in the shaft loop/s that means it's in correctly, same for the other side and once both caps are with the lock spring clips take a look and make sure they're centered, you can carefully adjust, press left or right if need.
Good Luck ~ :thumbup
