Back into the Rear Diff

Fun stuff... fun stuff.

So the Bronco has been great since the rear-end "rebuild" (brakes, bearings, seals, etc) and I'd been driving it all over the place.  So I get to my destination yesterday and when I come back outside there is a pool of rear diff fluid.

My initial thought was somehow the RTV seal failed but closer inspection revealed a hole in the rear diff cover.  It looks like from the inside out but clearly not catastrophic as the vehicle drives great.

The current theory is maybe a tooth on a gear broke.  It could be part of a broken bearing, a piece of dried mud with a rock / other debris, etc but I won't really know until I crack the case open and really look.

If it is a gear tooth you could run like that but for off roading it means less power to the rear which might cause some issues.

I'll know more once I crack it open and look.  The good thing was there was plenty of diff fluid still leaking when I got the Bronco home so minimal risk of any additional damage.

Rear-End Overhaul

So I mentioned in one post I thought a wheel brake cylinder was leaking and then in another post I said it looked like an axle seal.  It was actually both!

I started by lifting the leaky side (rear driver's side) with a jack and placed the driver's side of the rear axle on a jack stand.  I could see fluid all over the inside of the hub as shown in the left photo. In the right photo you can see fluid leaking out of the end cap of the wheel cylinder; the shiny spot below my thumb.

I also noticed that the brake shoes were looking really bad.  Again as you can see in the left photo part of the shoe was actually broken on one side.  The right photo also shows the new shoe to give an idea of how far down the shoes were worn.  Keep in mind I bought this Bronco in Feb 2014 so a lot of these things were worn well prior to my time and I'm learning about them as they come up.  That's part of owning an old car especially if you don't know the history on it.  Just expect things to break periodically and going to the parts store to fix it.

So back to the axle seal... to do that you have to lift both sides of the axle and it put on jack stands.  Two reasons for this ... 1) you have to remove the axle and 2) if one side is leaking the other side is probably not far off either.

So one you get the rear-end on jack stands you need to crack open the rear diff.  To do this set a big pan below to catch the fluid and remove the bolts around the cover.  I recommend keeping one bolt (half way out) at the top so the pan doesn't fall into pan and make a mess.  Once the bolts are off you need to use a rubber mallet or comparable to tap the cover until the sealant gives and the pan comes loose.  You may need to pry the cover but do so gently so you don't bend the edges of the pan.

Once the pan is empty you have to remove the bolt holding the pin between the two shafts.  In the left picture you can see the pin its the cylinder in the middle of the picture.  The pin's head is facing the passenger's side and you need a wrench to loosen it and then it slides out.  You can see the pin in the right picture.

When the pin comes out the bolt should slide out easily.  Don't freak out if a spider gear comes out, you can put it back in place.  Now that the bolt is out you can push the axle on each side in towards the diff and it will have a C shaped retainer you can remove (picture below with the bolt, pin, and diff cover bolts).

Remove the axle shafts and then you'll have access the the axle seals and bearings.  I used a seal puller to pull the leaky axle seal.  One of the interesting things was someone tried to previously repair the seal leak with RTV around leaky axle seal.  It clearly worked as a temporary fix for a few months but its not a long term solution.  And while this sounds like a lot of work its not hard to do if you have the right tools.

Funny enough one of the bearings was stuck so I rented a bearing puller from the auto parts store.  Worked great and then the other side came out no issue with a light pull but many parts stores have free tool rental so it saved what could have been more headache.

Installing the new bearings was easy.  Use a bearing race and driver kit and pound the bearing in until it stops. Then pound the axle seal in place.  Some people will try and use wood or something to hammer in a bearing and I find spending a few dollars on the right tool makes the process easy and ensures you don't damage a bearing/seal or drive it in crooked.

Once all that is done you slide the axles back in, connect the C clamps, put the bolt in, and re-attach the pin.  Run a good bead of RTV around the diff cover (lean off old sealant thoroughly first) and close it up.  The front of the diff on the driver's side has a 3/8" plug that you can remove to re-fill.  I uses a transfer pump and you keep pumping until diff fluid leaks out of the plug hole.  Ideally you want the truck to be on a level surface for this.

For the brakes I bought new hardware, wheel cylinders, brake cleaner, and a big bottle of brake fluid. Easiest way to replace the brakes it take a picture and use it as reference to put everything on.  Having a spring puller is helpful in terms of tools.

You'll need to bleed the brakes which is a 2 person job.  One person needs to hold the brake down while the other loosens the brake line at each wheel.  This should be done several times until the line no longer bubbles when the line is opened.  This normally takes about 4-6 attempts per side.

I was about $100 in parts for two bearings, two axle seals, two wheel brake cylinders, a brake hardware kit, and brake shoe kit plus brake and diff fluid.

Axle Seals

Upon further review the issue doesn't seem to be the brake cylinder as I mentioned but actually a rear axle seal leak.  You need 2 seals (one for each side) and they're normally about $5/ea.  Its a good time to replace bearings as well.

I have the parts but it will be a few weeks before I can do the work.

Be sure to order these seals sooner than later because most auto parts stores do not keep them on hand and they have to be ordered.

Updates upcoming when this project is complete.

Misc Odds and Ends

So in keeping with documenting things a potential owner or current owner of a Bronco might want to anticipate... more little things I'll have to address and some tidbits.

There was a big accident in Dallas towards the end of June and I was idling it the Bronco for well over an hour.  When traffic cleared I found that I couldn't accelerate and it was behaving funny.  I was able to pull into a gas station and determine it wasn't a fuel issue.  It acted like the battery was dead but I checked it and it was fine.  Radiator was full though I did notice some white smoke before the engine died.  After waiting for a buddy to give me a rescue tow to his place it miraculously started!

On the advice of a friend I tested the fan clutch as it was likely the engine had overheated [the temp gauge hasn't worked since I bought the Bronco].  A simple clutch test is to see how hard it is to turn when the engine his hot.  There should be resistance.

The fan spins freely when the vehicle is cold (since you want the engine to heat up to an optimal temp) but once the engine is to temp the clutch will engage locking the fan clutch into the same rotation speed as the engine for optimal cooling of the radiator fluid.  So in my case I wasn't getting enough cooling of the radiator fluid and eventually I overheated.  Once the engine cooled and I was at highway speed the air cooling kept the fluid cool.  So $60 and about 6 bolts later problem solved.  I also picked up a water pump for $30 and a thermostat to have when the time comes.

Next issue after all that was one of my 33s went flat.  Plugged a hole and found another one I couldn't patch so I had to put the spare on.  So next up will be another spare 33" tire.  I can probably find a used one for $50.

Lastly, I noticed that the brake performance has been getting poorer and found that brake fluid was leaking from that same wheel that went flat.  So that means the wheel cylinder is leaking.  The generic store brand part is about $10 and you might as well do both sides.  The store brand brake shoes are about $20/side.  So you're looking at about $60 in parts plus labor.  I'll probably handle this one over the weekend.

Dodge Grille Guard Install

I helped a buddy clean up one of his properties and he was nice enough to give me a grille guard off his old Dodge and bull horns.  I just felt they looked the part on this vehicle.  Let's be honest nothing about a Bronco says political correctness, conformity, green initiatives, or subtle.  And nothing about 33s, a winch, bull horns, or a grill guard says those things either.  Perfect match.

What wasn't a perfect match was mounting the damn grille guard!  There were no brackets and no good point to really make one to bolt it on.  If you'll recall from the winch install I used a steel plate bolted to the frame with a winch plate on top of it.  That was probably overkill but honestly I'd rather have too much than not enough if I have to winch out of a situation.

So ultimately I welded the guard onto the bottom of the winch plate.  Granted the welds might break if I really rammed into something hard enough but then again probably bigger problems if that occurs.

Harbor Freight Badland 9000lb Winch Fixed!

Been a while since I've done an update (been busy) but I fixed my winch the other day!

In April I installed a winch (see another post for the details on that) and the first day out on the trail, stuck in a really muddy spot, the winch didn't work!

As I may or may not have mentioned I bypassed the solenoid and ran power directly to the winch.  It was working but only in one direction.  A future thought was maybe when we welded the winch plate we forgot to unhook the battery and might have fried the solenoid.

So I was driving around with my winch line wrapped around my cut front bumper and before I knew it the 90 day warranty on the winch was up!

So before I bought another solenoid or winch I decided to re-evaluate the winch situation.  Luckily, I removed the old bumper and it made accessing the winch and plate much easier than with the bumper on.

The issue I was easily able to spot was simply that a small wire (probably 18 gauge) running into the winch and solenoid box had broken.  You can see the wire below (look at the red wire on the left side and you'll see that tiny dirty wire).   Reconnected that wire and back in business!

I left the cover off so you can sort of see what is inside the solenoid box.  As you can see there are numerous connector types and some bolts so any of these things could easily come loose.  As an added measure I ran some RTV around the edges before putting the box back on and plugged some holes (I left one small one open) to help prevent any water intrusion.

33s

A buddy ended up selling me his old tires because he was looking to get a bigger size.  These 33x10.5r15 tires fit my existing rims perfectly.  They do rub a little when making sharp turns but otherwise they work flawlessly.  There is an increase in road noise on the highway but its not like the Bronco is a quiet vehicle to start with.

The photo above was from a few weeks back.  Unfortunately, all the mud/water fried my solenoid on my winch so I will be working on repairing that soon.

Another issue was the power steering pump went out.  It was working intermittently but the Bronco is not easy to turn at low speeds without the pump.  The picture above is the old pump.  I was able to purchase a reman unit with reservoir from the parts store for about $65 and I'll get another $7 or so back when I return the old unit.