Portamate PM-P254 Router Motor Rebuild

I have not yet fitted a Portamate router motor into a horizontal router table; I have only ever used it in a vertical router table. At some time I would like to make a carrier for it so it can be fitted into a horizontal router table and give it a try.

I’ve used a few of the Portamate PM-P254 router motors though, which all start off working well but soon start making worrying noises, particularly when starting up and shutting down.

The Portamate PM-P254 router motor has plenty of power, and the speed control has always worked well, but in my experience the bearings are very poor. One set of bearings has Indonesia stamped on it and the other, China. So I decided to strip down two of the motors and replace the bearings. I’m glad I did because the bearings have failed in both routers. In both cases they have failed after only a few months of moderate use in my home workshop.

The smaller of the two bearings, situated at the ‘brush’ end of the motor is the one showing the larger degree of failure in both motors. In one the bearing is too stiff to revolve and the other has excessive side play in it. So I’m going to replace them with SKF bearings. At the same time I’ll give the motors a thorough clean and also replace the stiff plastic power cord with a good quality flexible cable. I think then I’ll have two router motors that will be better than when they were new.

I’m fitting bearings supplied by Bearing King who provide a really good service with free postage.

The two bearings are:

  • 6000-2Z-SKF Shielded Deep Groove Ball Bearing 10x26x8mm
  • 6004-2Z-SKF Shielded Deep Groove Ball Bearing 20x42x12mm

The first job is to take off the end cover by removing four Philips screws.

Portamate PM-P254 End Cover removal


Lifting end cover up reveals switch terminals, speed control circuit board, brushes and associated wiring. Unplug the  lead of the speed control adjustment knob from the circuit board. Pull off both terminals from on/off switch. The end cover can then be set aside.

Portamate PM-P254 pcb board


Then, the three screws securing the circuit board are removed and the board can then be lifted off, which exposes the speed control ferrite magnet.

Portamate PM-P254 wiring


The ‘closed end’ crimp terminals are removed and the speed control circuit board can be removed from the motor.

The connector wires can be detached from the brushes and the brush boxes lifted out after removing retaining screws.

Portamate PM-P254 brush box

Next, the speed control ferrite magnet is removed. This needs to be done carefully as it’s only a 4mm thread and made of soft metal. Before refitting it I recommend cleaning the thread out with a 4mm tap.

Portamate PM-P254 ferrite magnet speed control

I then remove the four screws that secure the stator housing.

Portamate PM-P254 removing stator housing


Then, with the stator housing uppermost, and secured vertically, held by its collet  in a vice, I carefully prise up the stator housing to release it from the small bearing. Using a puller I withdraw the bearing from the armature.

Portamate PM-P254 removing small bearing

Next I wrap a strip of leather around the armature and also place a short 4.5mm pin through the hole in the end of the armature, and carefully snug it up in the vice while I undo the collet with an air impact wrench. It comes off very easily.

Portamate PM-P254 removing collet

The bearing pressure plate can be unscrewed and lifted off along with the air inlet shroud.

Portamate PM-P254 bearing pressure plate

Next, I tap out the armature that slides out quite easily along with the spacing washer, fan and air deflector.

Portamate PM-P254 armature, fan air deflector

All that’s left is the motor body and main bearing. To extract this I used a 16mm bolt, nuts, washers and a plastic spacer.

Portamate PM-P254 extracting main bearing

Now they are completely disassembled, everything can be cleaned and then they can be reassembled with new bearings and brushes.

The first step is to press in the larger bearing in the motor body.

Portamate PM-P254 main bearing

Then refit the armature complete with fan, spacing washer and air deflector, and collet.

Portamate PM-P254 armature


Next press on the small 6000-2Z bearing:

Portamate PM-P254 small bearing


Then replace the stator housing

Portamate PM-P254 stator cover


And secure it with the four screws

Portamate PM-P254 stator cover


Then replace the bearing pressure plate and air inlet shroud.

Portamate PM-P254 bearing pressure plate


I refitted the brushes, and used new brushes, although there was very little wear on the originals.

Portamate PM-P254 new brushes


Reconnected the speed control mcb, fitted new UK colour coded cable using a good quality flexible rubber cable, and reconnected all wiring with closed end terminals.

Portamate PM-P254 Speed control mcb


Finally, reconnected terminals to end cover and fixed down with four screws.

Portamate PM-P254 End Cover

I’ve now completed rebuilding both router motors now, and it was well worth the effort.

When I first bought these router motors they were always a compromise, I was never really pleased with them but I didn’t see an alternative. There were other makes but they all looked like they were from the same manufacturer and just branded differently.

But now they have been overhauled with new, good quality bearings they are brilliant, what a difference.

They are now running much smoother, quieter and definitely better than they were when brand new. I could not be more pleased with them.