I am working with a friend who had a differential sandblasted for a late 60's musclecar. The blasting company made a mistake, and it has some blasting media inside the gear housing. We are cleaning it up, but I want to flush out the diff one or twice. I have a lot of cheap 5w30 available, could this be used to flush out the diff ? Whatever I use, the working plan is to top off the fluid, run it for 5-10 minutes at idle , in grear, on a lift, then drain out.
Flushing differential, what to use ?
- Thread starter rubberchicken
- Start date
Originally Posted by rubberchicken
I am working with a friend who had a differential sandblasted for a late 60's musclecar. The blasting company made a mistake, and it has some blasting media inside the gear housing. We are cleaning it up, but I want to flush out the diff one or twice. I have a lot of cheap 5w30 available, could this be used to flush out the diff ? Whatever I use, the working plan is to top off the fluid, run it for 5-10 minutes at idle , in grear, on a lift, then drain out.
I would use a straight 30 weight oil over a Multi-viscosity oil for the flushing, but ultimately it probably doesn't matter either way as long as the insides get cleaned and free of foreign material
I am working with a friend who had a differential sandblasted for a late 60's musclecar. The blasting company made a mistake, and it has some blasting media inside the gear housing. We are cleaning it up, but I want to flush out the diff one or twice. I have a lot of cheap 5w30 available, could this be used to flush out the diff ? Whatever I use, the working plan is to top off the fluid, run it for 5-10 minutes at idle , in grear, on a lift, then drain out.
I would use a straight 30 weight oil over a Multi-viscosity oil for the flushing, but ultimately it probably doesn't matter either way as long as the insides get cleaned and free of foreign material
JHZR2
Staff member
Not clear why it would matter for flushing.
Id try to get all I could out manually, and maybe with some air, then use whatever cheap oil you had to flush it. Id probably do a second flush with the cheapest diff oil I could find, and then drain it and do the move around with more cheap diff oil. Im not sure if idling in gear on a lift will do much, Id think you would want the sloshing around from motion. So Id do the in gear on lift flush, then a few turns in a marking lot or whatnot to get the fluid moved about... Then drain that and see how things are looking. Perhaps then use a better diff oil for 1000 miles, drain and refill with a fluid of choice.
Id hope that is sufficiently conservative.
Another thought - why couldnt this be taken to a big parts washing tub and actually washed clean in solvent?
Id try to get all I could out manually, and maybe with some air, then use whatever cheap oil you had to flush it. Id probably do a second flush with the cheapest diff oil I could find, and then drain it and do the move around with more cheap diff oil. Im not sure if idling in gear on a lift will do much, Id think you would want the sloshing around from motion. So Id do the in gear on lift flush, then a few turns in a marking lot or whatnot to get the fluid moved about... Then drain that and see how things are looking. Perhaps then use a better diff oil for 1000 miles, drain and refill with a fluid of choice.
Id hope that is sufficiently conservative.
Another thought - why couldnt this be taken to a big parts washing tub and actually washed clean in solvent?
Originally Posted by JHZR2
Another thought - why couldn't this be taken to a big parts washing tub and actually washed clean in solvent?
I think the overall reason is cost. I checked with two local machine shops and they do not have something large enough to hold the entire rear end. Putting the rear end vertically , then using solvent to flush it out might work, but it still seems that we should remove the gear set and guts, and he is running out of money and his wife's patience. I was advocating on swapping out the entire rear for a reman / rebuilt unit, but he claims its a numbers-matching rear: also his last experience on a reman rear end for a pickup truck was a disaster. The unit was blasted with aluminum oxide- I was hoping it was soda blasted but checking with the company discovered otherwise. Neither of us has much experience with rear ends other than changing the fluid and seals, so serious work needs to get farmed out.
Another thought - why couldn't this be taken to a big parts washing tub and actually washed clean in solvent?
I think the overall reason is cost. I checked with two local machine shops and they do not have something large enough to hold the entire rear end. Putting the rear end vertically , then using solvent to flush it out might work, but it still seems that we should remove the gear set and guts, and he is running out of money and his wife's patience. I was advocating on swapping out the entire rear for a reman / rebuilt unit, but he claims its a numbers-matching rear: also his last experience on a reman rear end for a pickup truck was a disaster. The unit was blasted with aluminum oxide- I was hoping it was soda blasted but checking with the company discovered otherwise. Neither of us has much experience with rear ends other than changing the fluid and seals, so serious work needs to get farmed out.
Take it apart. Buy 2 cases of brake cleaner and clean everything. Be meticulous in your cleaning. You don't want sand in the bearings or the ring and pinion. Shouldn't take you more than 4 hrs. Pack the axle bearings and oil the bearings, put it back together.
Compressed air. Do a gear oil change and flush it a few weeks later. Maybe do yearly flushes for the next few years and call it good.
Idle driving with engine oil won't do a thing IMO. It needs to be able to stir up things and get hot.
Idle driving with engine oil won't do a thing IMO. It needs to be able to stir up things and get hot.
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I agree with oldhp. It wouldn't take much blasting media, missed by the flush to cause problems.
Originally Posted by rubberchicken
I am working with a friend who had a differential sandblasted for a late 60's musclecar. The blasting company made a mistake, and it has some blasting media inside the gear housing. We are cleaning it up, but I want to flush out the diff one or twice. I have a lot of cheap 5w30 available, could this be used to flush out the diff ? Whatever I use, the working plan is to top off the fluid, run it for 5-10 minutes at idle , in grear, on a lift, then drain out.
Remove the cover and flush with brake cleaner.
I am working with a friend who had a differential sandblasted for a late 60's musclecar. The blasting company made a mistake, and it has some blasting media inside the gear housing. We are cleaning it up, but I want to flush out the diff one or twice. I have a lot of cheap 5w30 available, could this be used to flush out the diff ? Whatever I use, the working plan is to top off the fluid, run it for 5-10 minutes at idle , in grear, on a lift, then drain out.
Remove the cover and flush with brake cleaner.
I would not go the oil route. The particles will tend to stick everywhere. Better to use a solvent, fill the diff, rotate it a bit and drain. But the real fix is to take the whole thing apart and clean each part separately. That's what I would do at this point.
Clean out the carrier housing with brake cleaner, and once you have it on the road and get everything warmed up, change the gear oil.
+1 oldhp. Disassemble and clean each part meticulously and reassemble. Sand of any quantity in a bearing spells doom. I think this is your own fault for not carefully sealing all openings before sand blasting. Ed
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Originally Posted by rubberchicken
I am working with a friend who had a differential sandblasted for a late 60's musclecar. The blasting company made a mistake, and it has some blasting media inside the gear housing. We are cleaning it up, but I want to flush out the diff one or twice. I have a lot of cheap 5w30 available, could this be used to flush out the diff ? Whatever I use, the working plan is to top off the fluid, run it for 5-10 minutes at idle , in grear, on a lift, then drain out.
How are you cleaning it up now?
I believe it would be better not to run any oil in it until you have done everything you can to get the grit out of it first. Gosh, I feel for ya'll. This sounds
like a job that will be very frustrating. Don't be like me and cut corners to save time. That would be my fight.
I am working with a friend who had a differential sandblasted for a late 60's musclecar. The blasting company made a mistake, and it has some blasting media inside the gear housing. We are cleaning it up, but I want to flush out the diff one or twice. I have a lot of cheap 5w30 available, could this be used to flush out the diff ? Whatever I use, the working plan is to top off the fluid, run it for 5-10 minutes at idle , in grear, on a lift, then drain out.
How are you cleaning it up now?
I believe it would be better not to run any oil in it until you have done everything you can to get the grit out of it first. Gosh, I feel for ya'll. This sounds
like a job that will be very frustrating. Don't be like me and cut corners to save time. That would be my fight.
Use car cleaner. Spray all bearings well. Repeat. Wipe out bottom. You want an oil where dirt will drop out of suspension, no detergent. I would use dextron III..It has enough ep additives. for short term use. Dirt can settle out . 2 changes. Then gear lube. A change after a week of use.
Rod
Rod
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Why isn't the company that made a mistake handling the issue?
The right way to do it is to disassemble as mentioned previously. There is no way to flush it properly. Axles need to be removed , the whole carrier cleaned and reasembled. There is a lot of oil movement in a rear end at speed. Blast media would destroy the gear set and axle bearings.
Has this grit gone down the axle tubes?
Originally Posted by rubberchicken
I am working with a friend who had a differential sandblasted for a late 60's musclecar. The blasting company made a mistake, and it has some blasting media inside the gear housing. We are cleaning it up, but I want to flush out the diff one or twice. I have a lot of cheap 5w30 available, could this be used to flush out the diff ? Whatever I use, the working plan is to top off the fluid, run it for 5-10 minutes at idle , in grear, on a lift, then drain out.
Trying to understand what happened here. Was the housing bare or did it have the internals with no cover? I would say the proper thing to do would be to take it all apart and clean out the inside with brake cleaner, wiping down everything until the lint free towels are clean. Depending on what type of carrier, either disassemble and clean everything or drop the whole thing in a solvent tank, obviously not if a clutch type diff.
I am working with a friend who had a differential sandblasted for a late 60's musclecar. The blasting company made a mistake, and it has some blasting media inside the gear housing. We are cleaning it up, but I want to flush out the diff one or twice. I have a lot of cheap 5w30 available, could this be used to flush out the diff ? Whatever I use, the working plan is to top off the fluid, run it for 5-10 minutes at idle , in grear, on a lift, then drain out.
Trying to understand what happened here. Was the housing bare or did it have the internals with no cover? I would say the proper thing to do would be to take it all apart and clean out the inside with brake cleaner, wiping down everything until the lint free towels are clean. Depending on what type of carrier, either disassemble and clean everything or drop the whole thing in a solvent tank, obviously not if a clutch type diff.
Is the axle out of the car? Spasm3 pretty much nailed it.
Personally, I've replaced Detroit lockers, axle shafts and ring and pinions laying on the trail, but a nice 60's ride should be cleaned thoroughly.
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Personally, I've replaced Detroit lockers, axle shafts and ring and pinions laying on the trail, but a nice 60's ride should be cleaned thoroughly.
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Originally Posted by Kira
Has this grit gone down the axle tubes?
No, it seems to be in the main diff cavity. It came in through a drain bolt hole in the rear cover that was left off. The blaster guy said "no worries, we tape that off with special tape and plastic" but it did not work out very well.
This was one of those deals where "a friend" did the work essentially free, but messed up. Now I am the next "friend" who is trying to help deal with the fallout.
Has this grit gone down the axle tubes?
No, it seems to be in the main diff cavity. It came in through a drain bolt hole in the rear cover that was left off. The blaster guy said "no worries, we tape that off with special tape and plastic" but it did not work out very well.
This was one of those deals where "a friend" did the work essentially free, but messed up. Now I am the next "friend" who is trying to help deal with the fallout.
Give you the benefit of real world advice renewing industrial equipment up into the millions of dollars and seeing them literally destroyed in short order because of sand blasting/glass beading. I use it all the time by default so just learned to deal with it because its the only way to clean some of the stuff I get commissioned to renew.
Simply put, given the grit size and gram weight of the media ( and its penchant to grab and hold to every crack and fissure)- anything short of a high pressure high velocity wash will NOT remove it.
That's assuming your wash stream finds every little particle in every nook and cranny in the first place. ( and you wont)
But don't worry, soon after reassembly they will float in the oil and find bearings and seals and that aluminum oxide or whatever will do its job diligently.
We ( and pretty much all industrial OEMs and rebuilders) coat the inside housings usually with orange Class H insulating enamel or whatever paint/coating is resistant to any lubricant or process chemical and let dry.
This is common with new castings as well.
It seals everything in and will actually assist in the casting desorbing chemicals into the oil.
If you got abrasive media in it- strongly suggest you do this.
Simply put, given the grit size and gram weight of the media ( and its penchant to grab and hold to every crack and fissure)- anything short of a high pressure high velocity wash will NOT remove it.
That's assuming your wash stream finds every little particle in every nook and cranny in the first place. ( and you wont)
But don't worry, soon after reassembly they will float in the oil and find bearings and seals and that aluminum oxide or whatever will do its job diligently.
We ( and pretty much all industrial OEMs and rebuilders) coat the inside housings usually with orange Class H insulating enamel or whatever paint/coating is resistant to any lubricant or process chemical and let dry.
This is common with new castings as well.
It seals everything in and will actually assist in the casting desorbing chemicals into the oil.
If you got abrasive media in it- strongly suggest you do this.