[calmore]

I have a couple of Lamb 116154-00 motors that I'd like to service and I have a couple of questions:

What's the minimum length of carbon brush? I intend to measure how much brush is left on the basis that if they don't need replacing yet I won't do so. (I have heard horror stories of new brushes failing after a few weeks)

There are replacement brushes availiable from Woodbridge. Are these genuine parts or pattern parts? (Heard bad stories about pattern parts being the wrong grade of carbon...)

The main chamber of the pumps has some surface rust that I'll obviously clean up and paint. I'm thinking that the insides are probably similarly rusty. Is it possible to separate the two halves of the chamber to paint the insides? if so, can they be put back together and will they stay together?

One last question, have read the document on the Ametek website regarding replacing brushes and it refers to using an "Orifice plate". What's one of these when it's at home?

[Kinver_Clean]

The brushes are around 1" long at start. If there is less than 1/4" left then you need to get replacements ready to fit as there is a risk of burning the armature. Once that happens it's new motors.
It will be OK to run your machine until you have the new ones.  I have found over the years it is a waste of time and money to replace armatures in motors as the never seem to last long and it is difficult to reassemble the vanes so that they do not vibrate themselves to bits.
Just keep changing the brushes and with care the large motors will last well. When you change them blow the carbon out of the casing being very careful of the winding wires as they break very easily.
When the time comes to replace them see if you can fit 5.2" units as they now have the same performance as the 7.2s and will last much longer between brush changes.
It is a good idea at the end of the day to run the vacs for a minute with the tank lid open to dry the units out.

[calmore]

Are there any disadvantages to smaller pumps?

Will a smaller pump of the same wattage shift the same amount of air, give or take?

[Joe H]

Calmore
Kinver_Clean is a very experianced and mature carpet cleaner who knows whats what re pumps and vac motors. You can trust him.
If he says    "When the time comes to replace them see if you can fit 5.2" units as they now have the same performance as the 7.2s and will last much longer between brush changes."    then you can take that as read.

[calmore]

I'm not doubting anyones knowledge, just asking the question.

As I'm sure you are aware it's not just the amount of air a motor can shift which is important, but also air watts and water lift to take into account.

Like a car, the specification isn't everything. It can be great on paper but rubbish when you come to 'drive' it.

Hence asking the question whether there are any downsides.

[calmore]

Anyone know what an 'orifice plate' is?

Ametek specify using one when running in but don't say what it is...