Ford 9" Gear Oil Replacement and Cleaning the Interior of the Housing

Indycars

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I have never changed the fluid in the rear axle since I built the TBucket in 1979, so it was time to do so. I talked with GRT1999 (Gary) about a small problem I'm having where the car twitches a little entering a long sweeping corner on the highway. It's happens when the clutches in the Traction-Lok final begin slipping, until that happens the car wants to go straight. It's a minor annoyance and most people who driven the car don't even notice, but I do. Gary talked me into just changing the fluid and adding two bottle of friction modifier, instead of sending him the 3rd member.

I found that a Lowe's two gallon bucket fits very nicely and keeps the dirt out and would allow painting if needed.

FP02_LowesBucket_03172.jpg

To help the fluid drain I parked a couple of halogen lamps under the center section for a couple of hours prior to pulling the 3rd member.

FP02_HeatedCenterSection_03115.jpg

I'm not an expert, but I'm not aware of any problems with the gears. Although it would be hard to hear something if there was a problem.

FP02_CloseupRingGearTeeth_03124.jpg

I did find the right axle bearing was rough when I spun it. I thought it would be a roller bearing, but when looking for new ones I got a clue that maybe it was a ball bearing, so I had to see for myself. Sure enough, guess that makes sense it can take a side load as well as a vertical load. It would have to be a tapered roller to do both.

FP02_AxleBearing-Ball-Sealed_03159.jpg

The bearings I have are sealed and have an O-Ring in the outer race, so therefore I would have to conclude it does not need lubrication from the fluid. Besides that the seal sits inboard of the bearing also. Try as I might, I could not find a Timken bearing number with the O-Ring. The only place was from Moser where I bought the axles and they wanted $90 for the pair. I bought two Timken bearings on Amazon for $40 without the O-Ring. I think I can get by without the O-Ring by using a thin coat of sealer on the bearing OD, with that and the seal I should be fine.
Timken Bearing PN: RW207CCRA),
Bore Diameter (in.): 1.378 in. Outer Diameter (in.): 2.835 in. Width (in.): 0.845 in. [This is the small bearing.]
Seal is a National PN: 9569S

This axle has led a rough life before I got it, so in the video and photos you will see how it looks much nicer after I'm done.

FP02_AxleFlange-Left_03149.jpg

I know I'm going to catch some flack for this ! But I used a couple of flap wheels to clean up the axle bearing and seal area. Then some emery cloth inside the center section. It sure looks better and after I flush the axle housing with solvent several times while running a brush thru it with a drill I plan on removing any grit left by my previous actions.

FP02_DirtyInsideAxleHousing_03171.jpg
FP02_DirtyCenterSectionInterior_03134.jpg

I have planned to put a 1/2-20 magnetic drain plug in so I drilled off-center from the ring gear so anything protruding into the housing would not hit. Before I drill for the drain plug I started with 1/8" NPT so I could fit it with a fuel line barb fitting. Then after I'm done cleaning I can drill for the 1/2-20 thread. To help me drill straight I used the steel block to guide my drill.

FP02_DrillForDrainPlug_03142.jpg

I also fabricated a 3/4" plexiglass plate to go over the center section to create a reservoir. To add solvent I just pour it over the top. All I needed was about a quart.

FP02_PlexiglassPlate&BarbFitting_03177.jpg

I lowered the axle on the far side of the car in the video about 3 inches to make the solvent run down hill to the center section, probably should have gone with 4-5 inches. I didn't have as much trouble when I flushed the other side with the solvent flowing backwards and coming out at the wheel end.


I'm going to remove the magnets for the clear plastic lines and clean them. Then start all over again with new solvent and re-install the magnets to see if I'm getting any more trash during the 2nd cleaning.
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I love the pictures and detailed info!
btw Id add ceramic magnets to collect metallic trash, I did that in mt dana 60 and its amazing the trash they collect.
just be cerain to place then well away from moving components in recessed areas

 
Figured I would put the four Neodymium bar magnets inside the center section before I put the 3rd member back in. Probably up on the sides about 1/2 way up. Do you think that's far enough away ?
 
put them as far away from the ring/pinion gears, ideally in some corner recess, as you can get them, and they should be ok
I would not go any larger physically than the ones I linked too.
in fact I might go a bit smaller, like these
next time you inspect it youll be amazed at the metallic crud that was trapped and kept out of the meshing gears and bearing surfaces

 
Well you can't argue with counting the number of teeth on each gear and that's what I did. The ring gear had 32 teeth and the pinion gear had 9 teeth. So I have to correct myself from the 3.7 that I thought I had for years to the 3.88 from the numbers on the ring gear 35/9 to the REAL RATIO of 3.55.

I finally noticed after all these years that the rear drums were not exactly the same shape, so I decided to get new ones while I could still get them. Well that lead to new springs and that lead to ..... well you know the drill. The brakes are nearly completely new down to the springs, shoes, wheels cylinders and drums.

Then I figured out that Cerakote MC-5100 for polished aluminum is impervious to brake cleaners and also Acetone. I did the test below and I already had experience with Cerakote and acetone. This Cerakote feels like a non-stick skillet, it very slick and hard. So I coated the inside of the brake drums, wheel cylinders exterior, axle retainer plate and nuts etc.

Cerakote - CERAKOTE CLEAR - ALUMINUM

FP01_Cerakote_MC5100_BrakeCleanerTest_03253.jpg
FP01_Cerakote_MC5100_BrakeCleanerTest_03254.jpg

FP06_CerakoteInsideDrum_03288.jpg

While I had the chance I drilled the axle housing for a drain plug. I used this steel block to keep my drill straight.
Drain Plug PN: Votex DP004 (1/2"-20 x 25mm)

FP06_DrillGuideForDrainPlug_03142.jpg

Got to have some magnets, so I added 4 Samarium Cobalt disk magnets and a magnet drain plug.

SmCo Samarium Cobalt Disc Magnets - Applied Magnets - Magnet4less

FP06_MagnetsInRearAxle_03276.jpg

Also instead of painting where the wheels seat on the drum I used Cerakote there. Before the wheel would always pull the paint off the drum, I'm hoping this will solve that problem. See last photo.

I should be able to just spray Brakleen whenever I have the brakes open and it won't remove my coating. I'm planning on spraying my valve covers at some point, I'm really liking this coating.

FP06_CerakoteRearBrakeAssembly_03294.jpg
FP06_CerakoteRearBrakeAssembly_03299.jpg
FP06_BrakeDrumCerakoteAndPainted_03287.jpg
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To follow up and bring this thread to a conclusion. I have now replaced all the rear brake lines with Ni-Cop , -4 AN fitting and SS braided flexible line from the master cylinder to the wheel cylinders.

I had to drill the NEW Dynamic Friction drums for a 5 inch bolt circle. To do this I 3D printed a fixture to center the old drum with the new drum and then center punch for the 5" bolt circle.
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FP05_DrillNewDrumsForLarger5BoltCircle_03261.jpg

After drilling the first two holes I would use the 1/8" drill bit to index the two drums and center punch the other 3 holes.

FP05_DrillNewDrumsForLarger5BoltCircle_03266.jpg

After all was done, I did have to drill a couple of holes an additional 1/32" oversize before it fit over the wheel studs. This really should not effect the operation of the drum since it centers off the big center hole where it goes over the axle and NOT the studs.

Today I fired it up and let it run in gear for approximately 15 minutes before I took it off the jack stands to mix the gear lube with the friction modifier. Then went for a 40 minute drive, the axle and brakes all worked as expected. Checked the center housing temp when I returned, it was 100°F.
 
I love the clear pictures and detailed instructions
 
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I have never changed the fluid in the rear axle since I built the TBucket in 1979, so it was time to do so. I talked with GRT1999 (Gary) about a small problem I'm having where the car twitches a little entering a long sweeping corner on the highway. It's happens when the clutches in the Traction-Lok final begin slipping, until that happens the car wants to go straight. It's a minor annoyance and most people who driven the car don't even notice, but I do. Gary talked me into just changing the fluid and adding two bottle of friction modifier, instead of sending him the 3rd member.
Thought I would report back on this problem that I noted in the first post of this thread.

Until now I had not driven it in the right conditions to test the problem until yesterday when I took 120 mile trip to car show in Rush Springs Oklahoma and the Watermelon Festival. I'm glad to report that the problem has complete gone away. Thanks to Gary for talking me out of sending the unit to him and just changing the fluid and adding two bottles of friction modifier.
 
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