Sealey pillar drill strip and replace bearings GDM30A

My workshop is sadly a place that good tools go to die! This one is no exception and I've had this drill for a few years now- I bought it second hand and its pretty old by now- obsolete very possibly having been replaced by the GDM50. That drill is more powerful but apart from that has only minor updating from my model 30.

Anyway its started making some horrible graunching noises and has a definite tight spot in rotation. I hope this isn't a bent drive spindle, but having eliminated belt tension I think the bearings are a likely culprit. The motor turns easily when disconnected and although the noise isn't as bad when the spindle is spun by hand I can detect some graunching noises using the tried and tested screwdriver-to-the-ear method. The motor bearings in contrast sound smooth.

This is the parts list for the drill. The spindle (58) passes through a sleeve (56) and into an upper spindle cover (65) which also holds the drive pulley. The upper spindle has 2 bearings (66) separated by a plastic spacer and the lower sleeve another two (61 and 59) fitted in the top and bottom. Upper sleeve bearings are type 6203ZZ and the lower sleeve (despite having different numbers in the chart) are both type 6201ZZ. Both types are readily available and  Sealey parts are in stock at CCW tools. However at £12-16 each this pretty much makes repair uneconomical when a 350w Silverline bench mounted drill is available new at only £70 or so. I shopped around and got Dunlop versions of both types for about £2 each. I'll try replacing these first although I do suspect I need new brushes as well.

Firstly Some general views before I start- I don't have a stripping manual (!) so I want a record of what was where before I start.

So first step is to remove the drive belt and unscrew the nut retaining the spindle drive pulley. This is a reverse thread 1/2 WW


Hold the drill chuck in a mole grip and it comes off fairly easily



The pulley stack is one piece and levers off carefully with a screwdriver.

Undo the 4 Phillips screws that hold the belt guard on and remove it. It handily lifts over the motor drive pulleys.

The upper bearing of the 4 is then revealed, as its top protrudes from the housing. To be frank-with hindsight I think this was probably my entire problem and simply tapping this back down might have sorted it. It wasn't until I reassembled that I realised that in fact there is room for this bearing to sit flush in the housing and this is presumably its correct location. However I didn't know that at the time and anyway changing the bearings should do no harm...?
Remove the grub screw using an Allen key

 Then refit the top nut and carefully tap it upwards using a soft punch, turning the shaft to equalize the pressure until it lifts clear.

 Withdrawing the spindle sleeve and its two bearings (note plastic spacer in between.

Remove the depth stop collar from above the chuck- one Phillips screw and then it just clips off.

The spindle itself is still held by the drilling handles so remove the double nuts that secure the handle shaft and return spring cage.

The return spring is coiled in the black housing beneath- it will unravel as you pull it off the handle shaft but it only seems to be under about half a turn of tension anyway.

The spring fits into a slot in the end of the handle but once off the handle can be withdrawn. Support the chuck as you pull the handle out because the shaft will drop free.

 It slides out easily revealing the gearing rise and fall mechanism on the handle.

At the same time the shaft cover also falls out (hence the need to support it above) and the ladder gear on the shaft is obvious

The upper bearing is visible at the top of the cover- note circlip retaining the bearings.

Remove the circlip and tap the spindle downwards through the sleeve. The lower bearing comes out with the shaft as you do so.

Shaft and sleeve- upper bearing remains in the top of the sleeve.

The upper bearing remains in the sleeve tube but is easily tapped out from beneath using a flat faced soft punch.

The chuck is a morse taper fit on the spindle and just taps off downwards. Lower bearing still on shaft.

 The lower bearing is tight on the shaft. Its tight up against the ridge above the chuck so it has to come off the long way round! I started it using a socket to tap it down and completed it using equal side blows - its a bit of a  fuss and I feel sure I can find a better way if I have to do it again. The bearing is tight all the way along and I'm a little worried about how to refit, but I think I  may have to freeze the spindles before fitting the bearings.
I couldn't use this method for the upper sleeve as I didn't want to transmit any force through the plastic spacer. Eventually I used  a large socket to support the lower bearing and pressed down on the shaft end using a socket  so that no force went through the plastic.

The upper bearing was then free and could be removed with the plastic spacer.

Note that this bearing pair has their inner covers removed. I'm not sure if this is necessary and I don't intend to do that- my new bearings are shielded and I'll leave both covers in place.

The shaft was then pressed out of the second bearing using an appropriate combination of sockets as above.

Reassembly was pretty straightforward. I didn't take any pictures but I will make the following comments.

I did chill both shafts down to -20 in a domestic freezer before fitting the bearings. The shaft bearings then went on much more easily and

no longer bound all the way down, once past the upper bearings location point the bearing simply dropped down the shaft and could be pressed into position using a metal tube sleeve.

I used the press in combination with the holes in the press-plate and sockets to support the bearings such that pressing onto a shaft- press on the inner race only, and pressing into a housing, press on the outer race.

When pressing bearing onto both spindle and sleeve it is important not to press then too far because they do tighten up, I had to back them off a couple of times to preserve free rotation.

I replaced the "C" clips using E clips because I happened to have these but they located more positively.

I reassembled the shaft and sleeve into the housing- that's when I found that the upper bearing can and does recess nicely flush into the top of the drill. However it is important that the drive belt runs horizontally between the two pulleys when the spindle sleeve pulley is pushed down firmly nto the taper. If you simply pusheverything down as far as it will go the belt will be tipped down at the front. As soon as you run the drill the drive bet then lifts the pulley block up the spindle taper unscrewing the retaining nut to allow it to rise. This I found was the cause of my problem with this drill- in use the sleeve and its bearings was being gradually pulled upwards- out of the housing and unscrewing the nut. This created noise and weakened the drive transmission to the sleeves. It took a few goes but through trial and error I did manage to position the bearings and sleeve such that the drive belt was hoorizontal and there was no "lift" tendency when the drill was operated. In this position the pulley block remained firmly on the spindle taper and rotated clear of both the drill housing and the upper belt cover mounting screws.This made rotation much quieter and smoother.

Anyway I completed reassembly and it was as they say, the reverse of dismantling. The shaft seems a bit tighter... Probably didn't get the bearings loose enough on the plastic spacer of the upper shaft but I think it will loosen up with use. Good news is that the horrible graunching has gone and everything runs smoothly and quietly... Job done I think!!!