OT...Roller bearings rust frozen in aluminium housings.

[john.k]

I have an antique motorcycle engine...put together similar to a Harley ....water in the crankcase has frozen the whole assembly together .......what I need is to soften the rust in the roller bearings ,rust removal not necessary .......once the rollers are freed ,the crankcases can be separated without damage ...........I had the same problem with a 1936 version of the same motor,and tried to press it apart ,and broke one crankcase.........Is there any chemical that will soften the rust ,and not injure the aluminium.......Ive tried Evaporust ,it removes rust,but not the rust in the bearings.

 

[Robert R]

Alum or Cream of Tartar can be used to remove rusted steel bolts in aluminum castings. The hot solutions will dissolve steel and leave the aluminum intact. There are how to guides that will show up with a internet search. This has been covered in earlier posts on the PM site.

 

[BT Fabrication]

any steel frozen in aluminum is always a pain to remove. Alum can work to eat away steel, but it depends if you need both to come apart. Only luck i've had is torch heat and lots of spray lube.

 

[john.k]

Basically ,the cases will come apart if I can release the bond of the steel mainshafts on the roller bearing inner races ...steel on steel.....The cases will also come apart if I can release the grip of the steel rollers on the bearing outer races ...The cases will also come apart if I can release the steel races from the alloy cases .......they should be free to drop out with the cases heated to 250F ......but I know from the 1936 ,that the grip is augmented by rust ,and heating to oil smoking temp will not release the races ,and pressing through broke the D/S case ....it broke like cast iron in my hydraulic press.

 

[john.k]

I have some nitric acid ,and will try a few drops on the shafts to see if they will free in the roller bearings.......see claimed nitric acid is very penetrating and if it penetrates ,the rust will dissolve.

 

[Scottl]

Any good penetrating oil should work if given enough time. I don't know if you can get Trizol Creep over there but it is a water based penetrating oil that can be used with heat. I've even removed a cast iron plug in a cast iron soil pipe that hadn't been touched in over 50 years without harming the threads and was able to reuse the plug (with anti-seize). This is one of those thin hollow back plugs that plumbers usually remove by breaking out with a chisel. Late on a Sunday and no truck full of parts so I used a torch and Creep.

 

[Pathogen]

Povidone Iodine 10% same stuff you put on cuts

Put some to it and let it set overnight

 

[Bill D]

EDTA and water is the main component of evaporust.
BilLD

 

[john.k]

True,but Ive priced EDTA4Na ,and its same price as Evaporust.

 

[kustomizer]

Vibration is a powerful tool, what are we taking apart?

Ive put many a thing in heavy plastic bags and in the tumbler for a while to loosen them

 

[john.k]

The motor is a 1939 Panther 600cc single ......I have a 1936 with broken crankcases,as well as a 1948 motor for spares .........There is no urgency ,but at my age ,I wont be putting it aside for another 20 years.........I intend to try vibration using a small air hammer .........The 1936 motor was possibly less stuck ,but after 1year of soaking,attempt to press out the drive side shaft broke the case...........Endgame is to cut out the driveside mainshaft by drilling/milling/oxy.....this will free the cases,but destroy the shaft.

 

[mattthemuppet]

I'm a firm believer in multiple heat/ freeze cycles for freeing up rusted/ seized up fits. The cyclic expansion and contraction helps crumble the rust, combined with some flushing with a penetrant or Freeze Off, usually does the trick.

 

[Bill D]

True,but Ive priced EDTA4Na ,and its same price as Evaporust.

Your chemical prices must be very high. In the USA enough EDTA powder to make 10-20 gallons is less then the cost of one gallon of evaporust liquid.
Bill D

 

[john.k]

Every kind of price is very high here ,unless you buy industrial packs .....in this case a 50 gal fibre drum of chemical.

 

[Laverda]

Although alum will dissolve the rust it will also dissolve any carbon steel it touches. The aluminum will be fine, the crankshaft, maybe not so much.

Nitric acid may work as it does dissolve rust and if not a full strength acid will form aluminum nitrate on the surface which will protect the aluminum from the acid.

I would either put the entire crankcase/crankshaft assembly in a ultrasonic cleaner for a few hours or take it to a automotive machine shop and put in the hot tank they use for aluminum engines.

As for the bike, a 1936 Panther 600cc would be a model 100? Very cool bike!

 

[john.k]

The nitric is the stainless weld cleaner with some HFl in it.............I dont want to dip the lot ,just try to run a few drops down between bearing and shaft........I used the nitric on steel some time ago ,and it left deep pits next to shiny metal.

 

[keithmech]

heating till oil smoking is not hot. You need heat and lots of it.
bearings are cheap, smash them out, melt them out. Save parts hard to get.
destroy the cages and all the balls fall out .Now you have inner race on crank and
outer in block.Now it is easy and nothing gets broken.Run a weld inside outer race
it falls out when cool.welds shrink.Grind or machine off inner race.
I would be more afraid of the press than heat.