Cooling System Rehab Par’ Deux

Sorry it has taken me so long to get back to Part Two of this story! We took another trip and I’ve been working on a small electrical project that I’ll write up shortly.

As I left off, I had the cooling system bay empty and cleaned up, the radiators were refreshed and the next step was to refurbish the fan blower gearbox. I had to take the whole assembly to a truck repair shop to pull the fans, but once that step was completed I set the gear box up on my workbench and started taking it apart. Here’s a shot of the right fan shaft after I removed the bearing cap.


This was the side that was leaking the most and in the next few pictures you’ll quickly see why!

Before I get to that though, if you ever consider a similar project, notice that the bearing caps have shims underneath – for bearing end-play I would assume. I was careful to note their position and re-assemble the cap exactly the way it came apart. I was just renewing the seal, so I assumed if I put it back together the way it came apart and torqued things properly I should be OK.


Step 2 was to inspect the shaft to see how much wear was evident and while I didn’t measure it I could see a new seal would probably also leak.


You can see the groove the old seal has worn into the shaft.

Fortunately, my good friend Luke at US Coach has done this job a few times and knew (without asking) to include  ‘Speedi-Sleeves’ in my parts order! The sleeve is pressed onto the shaft to cover the groove and ensure a leak-proof seal. Here’s a shot of the parts I replaced on each shaft.


From left to right, a new O-ring, the Speedi-Sleeve and a new seal.

The sleeve came with its own installation tool, but it was too short to help me fit it onto that long fan shaft. So I had to run up to Dobbels, my favorite store, and wander the aisles until I found my special installation tool. Its funny as I’m not a ‘shopper’, but I can wander around a hardware store for hours. I found a 12″ metal kitchen sink drain pipe was exactly the right diameter to allow me drive the sleeve onto the shaft! So cool!

Here are a series of shots showing the installation:


I applied a little dab of JB Weld metal filler to the shaft at the groove and then positioned the sleeve on the end of the shaft.


The sleeve has been pressed on using my handy-dandy kitchen  drain pipe (special installation tool).


Here the new seal has been installed in the bearing cap and fits very nicely right over the newly installed sleeve.

Each of the fan shrouds have hard rubber scrolls on each end to help direct the flow of air to the center of the fans. I replaced my old scrolls as they had become brittle and broken over the years. Then it was a simple matter to reassemble the blower fan assembly.


The new rubber scrolls are installed in the ends of the fan shrouds.


The rehabbed assembly has been placed back into the coolant bay. You can see the end of the engine hoist chained to the assembly in this shot.


Its all back in place and the A/C compressor is back on top of the gear box. I didn’t lose any Freon either!

The next step was to get my refreshed radiators ready to install. Here are a series of shots showing that process:


The rehabbed radiator sitting on the tailgate. Heavy!


Its really important that the intake air be forced through the radiator rather than over/under/around/etc. So each radiator has metal and rubber seals that close up the coolant bay. The rubber was old and broken, so I replaced the old rubber and reused the metal scaffolds. Nearly all of the bolts holding these seals on broke during disassembly, so I had to buy new hardware and drill and tap a few captive nuts. I don’t have pictures of that, but it’s just drudge work and not very interesting. It is just one of those things you have to do if you want to do the job right.


The radiator with the new seals applied sans the old shutters.


I’ve got the passenger side rad installed here and I just finished sealing all of the little air leaks with spray foam. You can see the rubber seals seated against the fore wall of the bay on the left side of this picture.


A shot of the driver side rad all sealed in.


Here the body work has been reinstalled.

At this point, the hard and soft coolant lines have been reinstalled. There were some additional seals to totally isolate the coolant bay from the engine bay, but being made of unobtainium I had to roll my own. Below is a picture of one of those unavailable seals.


These things seal the holes for the hard coolant lines that run between the engine and coolant bays. There’s not much left of this one. I used some flat rubber and cable ties to seal the holes.

The last step was to replace the rubber seals on the coolant bay doors. The whole idea here is to open up the radiators (‘roddin’ them out) and then seal up the coolant bay so tight that air can only come in through the radiators! With the rehabbed fan blower, new scrolls and everything sealed up tight, it should work like its supposed to.



Its a dirty job, but who ya gonna call? ‘not rocket science’ as they say.

Post report: We took the MightyBus to Georgia and home via Indianapolis and I am pleased to report that we had absolutely no overheating problems! In fact, in cold weather it might actually be running a tad too cool!  I love it when a plan comes together.


3 comments on “Cooling System Rehab Par’ Deux

  1. Hey Jim Nice work!! did you have working shutters ever and did you re install them? we still use a manual “shutter’ system utilizing an old mudflap. About as high tech as the coach and myself. Thanks a lot for the posts and pics, dave and dori

    • Thanks Dave! The shutters have never worked since we bought the bus. I’m sure I could have fixed them, but folks I trust say I will never need them. In colder weather, the DD runs a little cool. The tradeoff is it runs cooler in hot weather than it used to.

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