Diagnosing Jeep Front Axle Noise

Diagnosing Jeep Front Axle Noise

Jennifer’s Jeep has been making a horrible grinding noise in the front lately. We tried putting it on jack stands and running it but we really could not tell where the noise was coming from.

There was some end play evident in the pinion so, since there has been a rash of pinion bearing failures around my shop lately we looked into that as a cause. I tried tightening the pinion nut but that did not help at all.

I finally pulled the front drive shaft and then removed both front axels from the housing. I replaced then with two wheel drive stub shafts. This eliminated the drive shaft, front U joints and differential bearings as potential sources of the noise.

The noise is still there. She has to live without 4wd for a bit while we wait for the new wheel bearing to arrive. While both wheel bearings feel fine when rotated by hand, one must be making noise when the weight of the Jeep is on it.

She also noticed that sometimes in hard right turns the noise will suddenly go away. This is another indication that a wheel bearing is the cause of the noise.
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Trail and Jeep Maintenance

Trail Maintenance and a broken U Joint

The last wind storm put a few trees down across the trails on my farm. The creek crossing spot has multiples angles that you can attack if from but they were all blocked by two large trees.

I finally got to use the new Chainsaw my dad gave me for Christmas. I took it out of the box for the first time. I was out of fuel so I stole a gallon from the ZJ that I have been working on. I hooked up my fuel pressure tester and jumpered the fuel pump relay and pumped a gallon into my small gas can.

I mixed in the little bottle of 2 stroke oil that came with the saw and filled the tank. Next I added chain oil to the reservoir. I also managed to spill oil all over the new saw and the floor. This oil is very sticky and hard to clean up, I might add.

It took me a moment to figure out how to switch on the ignition. The instructions say to flip the switch them pull the choke. Well before I broke the switch, I realized there was an interlock that causes the switch to flip as you pulled out the choke. I don’t see any other way to flip the switch on.

I pushed the primer bulb a few times and pulled the rope a few times. I was very happy that my new saw roared to life. I made a test cut and I was ready to go to work.

By that time it had started to rain lightly. Janice, Jennifer and I donned our rain gear and headed down the hill. I cut the trees into sections small enough for the girls to haul off the trail.

The first tree was easy, but the second one spanned the creek. Walking across the log was the only way to cross the creek with out getting wet. I walked across the log and found a way to cut the log loose from the stump and let it fall in the water so I could still walk on it.

I hiked back up the hill and got Jenny’s Jeep to help haul away the logs. I drove down in the creek and hooked a strap to the first long section. I drug it down the creek to a place out of the way. When I tried to back up, I got hung up in the mud and started to slide sideways against a tree the overhangs the creek.

I thought I could go forward and climb the bank further down. However the steady rain made the bank too slick to climb from that angle. I tried to drive on down the creek but I got wedged between a rock and the other bank in a narrow and deep section.

I finally was able to walk one front tire up the rock and do a rear dig to bring the back into the right angle to back up the creek. Then I was able to get the proper angle to climb up the creek bank.

One the drama of being stuck was over, I backed back into the creek and lined up to pull the remaining stump. The stump proved too heavy to drag down the creek. The Jeep just dug in and would not move forward. I did manage to get the stump clear of one of the paths across the creek and dislodged form the creek bank. I hoped that soon the creek would rise and move the stump out of the way.

The trail up the hill to the house was already getting very slick as we made our way back up. I had to use much more throttle than normal to climb it. Right at the top we heard a loud pop, but could not figure out what it was.

The next day, the overnight rains had completely flooded the bottom land and the creek bed looked like a lake. The stump was no where to be seen. It will be interesting to see where it ended up when the water recedes.

As I was hiking the trail, I noticed a U joint cap near the spot where we had heard the pop. I crawled under the Jeep and began checking all the U joints. I found the missing cap belonged on the driver’s side axle. Luckily we keep a spare around.

Twenty minutes later we had the spare shaft installed and she was ready to go again. Looks like the C clip twisted out then the cap worked loose. Another argument for welding the caps I suppose. I still have not tried welding the caps.

Dana 35 Yoke upgrade

Dana 35 Yoke upgrade

The modern Dana 35 holds the drive shaft with straps and bolts. The older Jeeps used U bolts to hold the drive shaft in place. The only difference in the yokes is that the newer one is tapped for threads to hold the bolts instead of being drilled for the larger U bolts.

This week I was reinstalling the straps on my rear drive shaft and stripped the threads on one of the bolts. Rather than try to repair the threads, I elected to retrofit the older U bolts to my yoke.

I used the U joint kit from Crown Automotive (A490K). This kit comes with two U bolts and four nuts and lock washers. They appeared to be over bent just a bit and I had to spread the legs to get them parallel. Otherwise the quality was fine.

I began by drilling 5/16 holes where the bolt holes were. These holes were a bit too tight for the U bolts so I used an 11/32 drill instead. The bolts fit fine in these holes. The casting of the yoke was easy to drill. I used water form a spray bottle to keep the bit cool.

I reinstalled the drive shaft and tightened the U bolts for a nice snug fit. The whole job took about 30 minutes.

If you don’t want to drill your yoke or if it is broken, you can get the whole kit including the yoke, a new seal and U bolts from Crown – part number D35-YOKE-UBK.

I will be modifying the front later using kit D3044-Yoke-UBK because there is not enough room for the nuts on the back of the stock yoke.

Machine Tool Safety

As I look at the scar on my left index finger, I am reminded of how fast a machine tool can cause an injury. I was a teenager working in my grandfather’s machine shop when it happened. I was using the large drill press to counter bore holes in the cutting edge of a bulldozer blade.

The drill press was very old and was definitely not built with safe operation in mind. I am not sure why, but the procedure involved sliding the heavy plate into position under the drill bit while the bit was still turning slowly in the chuck. I was wearing gloves to protect my tender hands from the sharp edge of the blade. The bit caught my glove, and although it was turning slowly, it began to wrap my finger around the bit all too quickly.

I was able to hit the power switch but the drill continued to coast until my whole arm was wrapped around the spindle. I reluctantly called to my grandfather for assistance. He manually turned the drill backwards as I unwrapped myself from the machine.

I was very lucky to have escaped with just a cut on my finger. I quick bandage and I was back to work; this time without gloves.

Machine tools can be very unforgiving when body parts are caught on or in them. The nature of the work also brings hands and fingers dangerously close to the rotating parts. It is easy to get accustomed to the proximity and get caught.

Gloves and loose clothing can easily get caught. Neckties should not even get close to the machines.

Procedures need to be developed to minimize exposure to the hazards. Making sure the rotating parts have stopped before relocating the work or taking measurements is one good place to start. I have seen many experienced machinist take caliper readings while parts are being cut in a lathe. Such practices endanger the worker and the equipment.

Guards are often a huge annoyance to machinists. However, if the guards are constructed of clear materials and made to easily open and close, they can add safety without interfering with the work to be done.

When developing procedures and procuring safety equipment, it is important to work closely with the machinists to make sure that the safety equipment does not interfere with the work. Otherwise, the safeties will be bypassed and procedures overlooked when supervision is not around.

Machine tools are a part of most modern workplaces. They can be used safely and effectively if proper precautions are taken.

Noisy water pump XJ

I have been hearing a rattle in my 91 Jeep Cherokee for a while now. I thought it was in the exhaust at first. But as it got louder, it was clear it was coming from the front of the engine.

I pulled off the idler pulley but the bearings in it were fine. I replaced it and reset the belt tension. The noise as defiantly coming from the front of the engine.

I got my mechanics stethoscope and began listening. The noise seemed to be the loudest at the water pump. I have never had a water pump bearing fail with out it leaking first. But that sure seemed to be the case this time.

I tried to ignore it for a day but the noise just got worse. I stopped by Autozone and verified that I had a warranty on this part that I had replaced in 2007 according to their record. I picked up a new pump and some antifreeze.

I was still skeptical but when I removed the belt and turned the pump by hand I could feel the bad bearing. I removed the pump using the procedure I have practiced way to many times.

I put the old pump in the vise and the noise was very clear when the pump was rotated.

I installed the new water pump and refilled the radiator. I found leaving the heater hose off the water pump allowed the air to bleed quickly.

Once I started it up it ran nice an quiet. The only casualty was that I broke by fan shroud while moving it around to get to one of the bolts. I will have to fix that before summer.

I took the old water pump back to Autozone this morning and got my money back. It was a very simple exchange. They had all the info in their computer.

If you want to get a 4% rebate on purchases from Autozone, use this link to buy online and pick up at the store. http://tinyurl.com/6fpp7se