leaky front bearing?

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xtremsavage

xtremsavage

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Jacksonville, Fl
I tried searching the forum but couldn't find any good results, but does anybody know how to check and see if the front motor bearing is leaking? Is there some sort of test that I can do to check it. Also, what's the best method to replace it and should both (inner and outer) be replaced or just the outer rubber sealed one? Also, what would be a better replacement over the original? Went to finish putting the truck back together the other day and noticed a puddle of red fluid (same color as the fuel I use) sitting under the truck around the motor area. Not quite sure if it came from the motor or not yet, gonna reclean around the motor and see if that's where it's coming from. Any help on this would be great.
 
Try a air leak test on the front bearing, if it leaks air it will leak unburnt fuel through it which would explain the wet engine casing, as long as the bearing inside turns smoothly it wont need replacing,
http://www.bocabearings.com/ sell some great bearings and are well known for supplying RC bearings.
I use a wrench extension bar and tap the bearing out, and use a press to fit new bearings, if you don't have a press use a socket that matches the size of the bearing and tap it in making sure it goes in perfectly straight (it is easy to damage your new bearing if not extra carefull)
If bearing is to tight to fit I would put bearing in the freezer over night, this will help it fit well. Hope this helps and makes sense!! :resp:
 
The front bearing is not the main seal in the front of the engine. The seal in the front of the engine is created with Oil and a tight tolerance between the front of the Crank and the nose of the Crankcase. When spinning the oil creates a thing layer around between the two creating a seal. However, there is a little oil threw a gully or hole to the front end which allows a bit of oil to the bearing more or less to keep it lubricated and the bearing needs to seal this stuff in. The front bearing can leak a tad but you don't want it to leak much. When blowing in a bit of air it should hold for the most part.

If it is leaking a heck of a lot what happened is either the bearing was completely shot and gave enough slop and messed up the smooth surfaces on crank or crankcase or you ran a lot of dirt threw your air filter.

Like said it shouldn't leak much.
 
Thanks for the replys guys. How do I do a air leak test on the motor? I'll clean around the motor again tom. or Fri. and then drop a bit of fuel trough the carb inlet and let it sit overnight. Then I'll check it the next day and see if and how much fuel has came out. Then I'll do the air leak test, once I'm told how to do it, that is.
 
To do a air leak test all you need to do is put a fuel line on the carb fuel inlet and plug exhaust and intake hole (Air filter hole) and blow into the Fuel line, whale spraying a water soap mix on it and watching for bubbles. Works well. There may be other ways but this is pretty easy.
 
Thanks Jason. I'll check everything out tom. afternoon if I get a chance. Also, I read some where else on another site that was linked through a different thread about when cleaning a motor. I believe Jeremy was the one who started the thread. But, anyways, in the article, when cleaning the motor and using nitro spray cleaner, it said to place a rag or paper towel between the front bearing and flywheel to protect the front bearing. My question is, will the nitro cleaner damage or harm the front bearing? Thanks again for all your help guys.
 
Nitro cleaner maybe similar to carb cleaner will tend to eat plastic. I have used nitro cleaner for ages now using brake cleaner which is fine on plastic but have never had a problem with nitro cleaner doing this. They may just have it noted to cover there butt.
 
I haven't done the air leak test yet, gonna today. I'll probably end going ahead and replacing the bearings any. I've decided to go with the boca's, I'm just not sure which ones. They'll be goin in a axial 28 spec1 s. The only motors that I seen listed on boca's website were for the 32 and 28 rr. Would the bearings for one of these motors work in the 28 spec1 s? I won't be able to get them for a few weeks. Just would like to know for when I'm ready to get them. thanks again for all the help.
 
If you Email [email protected] and tell him what mill you have, he will tell you what bearings will fit, I have dealt with him a few times and have nothing but good things to say about him. :resp:
 
I finally got the motor out. I have a feeling that it's not leaking from the bearings. I think it's actually laeking from the backplate area. Not where the backplate meets the block but on the inside of the backplate where the shaft goes through. The shaft feels like it has some play in it. I'm not sure it it's supposed to have any play in it or not. I'll look at the motor some more in a little while or tom. and I'll report back.
 
Update. Did an air leak test yest. and the bearing is leaking. Everywhere else is air tight. I'm gonna replace them with Boca's, but I'm not sure which ones. They don't have my motor listed, Axial 28 Spec1s. All they have listed is the 28rr and 32 Spec1s. Will I be able to use a set for on of those motors or not? If so, which set would be better replacement? Also, do I need to replace both or just the inner one, or would it be better to just replace both? Thanks for all the help again guys.
 
Thanks Crash, I had scrolled back up on where i was looking at the stock bearing sizes and i was looking at the .28rr parts so i wen't look at the parts list for the .28 spec 1s and they didn't have an listed so i looked at the .32 parts list and it had the same sizes as the .28rr. it looks to me that all of axial's engine bearing sizes are all the same so i think the ones i posted will work.
 
samrsnow said:
Might as well relpace both bearings...I did some research and i found that these are the exact same size as the stockers but they are listed for the .28rr

http://www.bocabearings.com/main1.aspx?p=product&id=14373&n=*ENK-161MX
Click to expand...

Thanks sam. I knew the bearings sizes were the same for all three motors, I just wasn't sure if it would harm the motor going with a bearing that's not actually listed for my motor. I was thinking about going with one of the ceramic type bearings. I beleive I read a post by purenitro that the ceramics are better choice for motor bearings. I'll look into it some more later on.

Crash said:
great advise sam
Click to expand...
Thanks Dan for your input on this too.
 
Another easy tip on replacing bearings is to heat the engine in your oven for about 20 minutes on 300 degrees. The engine will expand a tad bit with the heat and the bearings will almost fall out with just a slight tap. And like was mentioned previously have your new bearings in the freezer which will help them shrink a tad. Then the combination of a hot engine and ice cold bearings will make them fall right into place.


I always tend to use the TKO Ceramic bearings. They are really not expensive at all considering the last TKO front bearing I purchased cost about $15. If your engine doesn't have much fuel through it and the rear bearing is still smooth with no gritty areas I would replace just the front bearing. The inside bearing can be a pain in the butt sometimes if you don't have a lot of experience with replacing engine bearings.
 
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