1995 4020HT making noise - motor bearing?

[MBX5]

Mill has been shut down for a few weeks....fired it up today and warmed up the spindle....it is making a very noticeable sound coming from the lower motor area..It sounds bearing related - we all know the sound of a failing bearing... I know it isn't the spindle bearings - they sound OK.... It could be a tensioner bearing or the lower motor housing bearing...

Anyone have something like this happen? How bad is replacing a motor housing bearing? Anything special to putting the motor back on after removing?

Thanks!

[denmar]

Have to remove Pulley by heath it up with a 3000 btu torch.

[dunnitagain]

If it is a two speed spindle. It could have coolant goo on the belt. Kind of makes a funny noise as it runs across the pulley.

[carbidecraters]

It also could be the tension wheel bearings..these are usually the first to go if your not running the spindle hard.

[Delw]

Ive replaced motor bearings they are easy, however I never had them make noise.

if the noise your hearing kinda sounds like an air impact. its your belts due to coolant.
if you have black tar like on the tension rollers change your belts, you can clean them but it will only work for a week or two before you have to replace them.
if your running a face mill plan on changing belts about 1-2 years.
make sure all your covers are INplace. especially the one at the bottom of the head, if thats not there you will have premature belt failure ALOT.
In 20+ years 3 fadals I have never had to replace a tension roller or bearing. had one air cylinder go out.
Had to replace lower motor bearing twice in 1 machine due to alingment issues and bad pulley we had bought the machine used and broken anyway, so knew it had to be replaced.
Delw
.

[Neal]

Just a caution here--- If you remove any pulleys be VERY careful of the install height. If the two pulleys are not in line correctly you will trash belts.

Neal