B7100 Dynamo reaveals crud

[M3Stevie]

I'm still going over a 78ish B7100 that I picked up a month ago and playing catch up on fluids and the such. I honestly think it was a fuel and go machine for the past few years based on what I've seen. A slight belt tightening last night turned into failed Dynamo bearings this morning. I finally pulled the Dynamo off after a 2 hour struggle with corroded studs and was shocked to see jellyfish looking slime in the block. I read an old school technique for flushing with vinegar. Does this actually work? I hope to get to that point soon if I can find the bearings locally.

 

[85Hokie]

I'm still going over a 78ish B7100 that I picked up a month ago and playing catch up on fluids and the such. I honestly think it was a fuel and go machine for the past few years based on what I've seen. A slight belt tightening last night turned into failed Dynamo bearings this morning. I finally pulled the Dynamo off after a 2 hour struggle with corroded studs and was shocked to see jellyfish looking slime in the block. I read an old school technique for flushing with vinegar. Does this actually work? I hope to get to that point soon if I can find the bearings locally.

DID ya have fun getting the middle lower nut off?? Putting it back on is fun too!

White vinegar works well, need to run it up hot for a while, empty, and repeat. It will be better than it is now.

As for bearings, 6201 , this is a standard bearing you can get at NAPA or any place like that.

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your look something like this inside?

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[M3Stevie]

WOW, THANK YOU! You've just saved me a ton of time on a bearing hunt! Actually, I lucked out with that lower center nut.... I think the last time it came off someone gave up on it and didn't even bother putting it back on lol. I haven't broken the dynamo down yet to look inside. Instead, I chose to break down a couple of Coronas.

Thanks again for this great info.

 

[JeffL]

The slime is silicate drop out which occurs when the coolant is not replaced when spent. Supports your statement about the previous life of the tractor.
Problem using an acid (even mild) for flushing is neutralizing what will remain in the system. With that said, I used muriatic acid (5-10% Hydrochloric acid) to clean a really corroded system. Then cleaned up with flushing 10 times with distilled water and then changed the coolant after one year. Never had any issues from that. Jeff

 

[M3Stevie]

Thanks Jeff. Great info.

 

[NoJacketRequired]

The slime is silicate drop out which occurs when the coolant is not replaced when spent. Supports your statement about the previous life of the tractor.
Problem using an acid (even mild) for flushing is neutralizing what will remain in the system. With that said, I used muriatic acid (5-10% Hydrochloric acid) to clean a really corroded system. Then cleaned up with flushing 10 times with distilled water and then changed the coolant after one year. Never had any issues from that. Jeff

So how does one go about knowing the coolant is "spent"? I recently had somebody tell me that one could use an ohmeter to do a poor man's conductivity test, although I highly doubt the results would be meaningful.

I have three tractors which means a LOT of coolant so I'd rather not replace fluids based purely on calendar time. For my two orange tractors, I don't know when the coolant was replaced, but both of them show coolant that looks very fresh and vibrantly green in color.

I'm open to thoughts and well-proven techniques...

 

[M3Stevie]

Thanks Hokie! A/C Delco wanted $49.00 per bearing (they're close) and O'Reilly's saved the day at $1.99 each with one in stock, and one set up for a store transfer. Once I got the case opened the bearings were intact, but frozen solid. A hydraulic press is a must for pressing them out and in. Thanks again for your help!

 

[85Hokie]

Getting them out is NICE with a press, I tapped mine out - and going BACK in I used a socket that was large enough to go on the outer face of the race and placed the entire thing in a vise and slowwwwly tightened the vise. Bearing went in smoothly!

I think I bought two - for like 5 bucks and change!

 

[85Hokie]

So how does one go about knowing the coolant is "spent"? I recently had somebody tell me that one could use an ohmeter to do a poor man's conductivity test, although I highly doubt the results would be meaningful.

I have three tractors which means a LOT of coolant so I'd rather not replace fluids based purely on calendar time. For my two orange tractors, I don't know when the coolant was replaced, but both of them show coolant that looks very fresh and vibrantly green in color.

I'm open to thoughts and well-proven techniques...

I had heard this before too, here is some info on the subject

http://www.ve-labs.net/electrolysis-101/how-to-test

 

[JeffL]

Nice link to the electrolysis test. This test is for electrical/ grounding issues not a coolant condition test.
Large fleets use test strips to measure the pH as stated in the link. You can buy these from dealers for Cummins, Detroit Diesel, and Cat. and others. I would not use a visual test as by the time you notice something the damage is done. From reading various articles and manuals on coolant I have the impression life of coolant is mostly time dependent and less on hours/miles used. I'm sure running has some affect on life just less than time.

 

[lugbolt]

So how does one go about knowing the coolant is "spent"? I recently had somebody tell me that one could use an ohmeter to do a poor man's conductivity test, although I highly doubt the results would be meaningful.

I have three tractors which means a LOT of coolant so I'd rather not replace fluids based purely on calendar time. For my two orange tractors, I don't know when the coolant was replaced, but both of them show coolant that looks very fresh and vibrantly green in color.

I'm open to thoughts and well-proven techniques...

Test it with a volt meter, an accurate one. One probe in the coolant inside the radiator filler neck, the other probe on the radiator metal part itself. 0.6v and it's time to replace it. 0.4v is about normal. 0.8 and more, it's been junk for years and expect to have to replace the rubber hoses at some point. There is also the Ph test, that I have personally not done. The PH is probably more accurate, as the voltage is a function of the acidity of the coolant. The more acidic, the more the system becomes a "battery"-which is why the voltage increases. That is how a battery works. 2 dissimilar metals, with an electrolyte medium. The electrolyte is the coolant, the dissimilar metals are the engine and the radiator. I mentioned soft hoses because as the voltage increases, it is trying harder to pass from the radiator to the engine block, and the only way it can pass is through the rubber hoses, which softens them. That's one reason many old cars/trucks will have leaky radiator hoses; they were not serviced properly.

coolant and brake fluid are never serviced/replaced often enough....two of the most neglected systems in cars, trucks, tractors, etc.

The gel stuff you find in radiators is a function of several things, one lack of maintenance, two overheating and three, use of tap water. Never use tap water mixed with coolant. Always use distilled water; or buy it premixed 50/50.

 

[nickelplated5s]

- and going BACK in I used a socket that was large enough to go on the outer face of the race and placed the entire thing in a vise and slowwwwly tightened the vise. Bearing went in smoothly!

That was a press, just not a hydraulic one.