Help with my 7424xp

DETAILROOKIE

DETAILROOKIE

Well-known member
Joined
Jan 19, 2016
Messages
1,211
Reaction score
147
I was waxing my neighbors car today with a regular 5.5 inch foam pad by LC and my PC would spin slow then fast. It was never a constant speed even without any pressure. I let it spin in mid air and it would start off slow then go normal speed like it had to warm up first. I purchased this machine in 2014 and has been used a handful of times. What can I do to fix this issue or should Iook into getting a new machine?

Sent from my SAMSUNG-SM-G935A using Autogeekonline mobile app
 
DETAILROOKIE said:
I was waxing my neighbors car today with a regular 5.5 inch foam pad by LC and my PC would spin slow then fast. It was never a constant speed even without any pressure. I let it spin in mid air and it would start off slow then go normal speed like it had to warm up first. I purchased this machine in 2014 and has been used a handful of times. What can I do to fix this issue or should Iook into getting a new machine?

Sent from my SAMSUNG-SM-G935A using Autogeekonline mobile app
Click to expand...
Do you have the spare brushes. If so change the brushes and hopefully that is the repair

Sent from my SM-G955U using Tapatalk
 
I would think with just a handful of uses, that it shouldn't be bad brushes.

Have you also noted any increase in sound levels of the motor when running? Sometimes with bad brushes, a electric tool often gets noisier.

I would more suspect a Speed Control Dial going bad.

Not saying this going to fix the machine, but with the machine off or unplugged, try rotating the speed dial back and forth gently numerous times, and see if you note any differences in operation?

If any differences noted, even for a short period of time, I'd then suspect this speed dial control as the culprit.

Such a part I've just seen at one online vendor, about a $18 part plus shipping.
 
MarkD51 said:
I would think with just a handful of uses, that it shouldn't be bad brushes.

Have you also noted any increase in sound levels of the motor when running? Sometimes with bad brushes, a electric tool often gets noisier.

I would more suspect a Speed Control Dial going bad.

Not saying this going to fix the machine, but with the machine off or unplugged, try rotating the speed dial back and forth gently numerous times, and see if you note any differences in operation?

If any differences noted, even for a short period of time, I'd then suspect this speed dial control as the culprit.

Such a part I've just seen at one online vendor, about a $18 part plus shipping.
Click to expand...
The last time I detailed a car, last week, the vibrations were out of control and it was very loud, but it would calm down and work normally. This time there wasn't any noise issues but the pad wouldn't spin as it should. The machine itself sounded really low like if was trying to stay on.

Sent from my SAMSUNG-SM-G935A using Autogeekonline mobile app
 
If you're handy enough with disassembly-repair of such a tool, I would assume ordering a part-parts would be cheaper than having it repaired by an authorized PC repair business.

I've fixed many odds and ends over the years, finding businesses that sell parts for many appliances and tools.

That one would have to do a disassembly to inspect the brushes. If they are fine, then you'd at least assume that the problem then lies elsewhere, like the rotary speed control. Often bad brushes can make the Armature they ride upon look pretty bad, burnt.

One possibility is not worn brushes, but a bad or broken brush.

Was the machine ever stored in a possibly damp place?

I seen a speed control dial on the big auction site as well for $22 with free shipping.
 
I have a similar problem with my 7424xp. The brushes are $6 apiece and you need 2. Just google carbon brushes for porter cable 7424xp. There are 2 models, type 1 & type 2, just look on the badge it says that very clearly. Mine was type 1
I have mine on order but they shipped to the wrong location or otherwise would have them installed already, go figure. Mine started to make more noise and the rotation was very inconsistent.
Just take off the 4 torx screws on the handle, it will split in half. You can see one brush easily, the other is on the opposite side. Didn't look tough to replace at all, just fiddly.
When mine finally arrive I will update you.
 
What happens if you plug it directly into the wall socket?
 
Kevin845 said:
I have a similar problem with my 7424xp. The brushes are $6 apiece and you need 2. Just google carbon brushes for porter cable 7424xp. There are 2 models, type 1 & type 2, just look on the badge it says that very clearly. Mine was type 1
I have mine on order but they shipped to the wrong location or otherwise would have them installed already, go figure. Mine started to make more noise and the rotation was very inconsistent.
Just take off the 4 torx screws on the handle, it will split in half. You can see one brush easily, the other is on the opposite side. Didn't look tough to replace at all, just fiddly.
When mine finally arrive I will update you.
Click to expand...
Great thank you! I'm ordering mine today.

Sent from my SAMSUNG-SM-G935A using Autogeekonline mobile app
 
Do you have the compression washer between
the machine and backing plate, just a thought.

Jim
 
When my PC 7424XP was brand spanking new, it ran like crap at first. The speed would vary a lot, all on its own. I would set the speed control to 6 and while free-wheeling it, the speed would be all over the place. It would speed up then suddenly slow down, then speed up, then bog down again..... I put a backer plate and pad on it anyway and tried it again. Just as before, it was running really slowly and then all of a sudden it puked out a bunch of white grease from all the vent holes. It seriously blew grease all over the place. All over my apron, the backer plate, the car I was standing next too, etc... I shut it off and wiped up all the grease, cleaned up everything and then used a Q-tip to get the rest of the grease out of the 7424XP's vents. Fired it up again and it has ran like a champ since. My 7424XP just seamed to be way over-packed with grease at the factory, so much so that the machine was bogged down by all the grease. Once the machine had flung it all out the vents, it has been fine since.

Could this be the OP's problem?

Has this happened to anybody else? Is this common?
 
I have had no performance problems from my PC7424XP. I ordered mine in 2014

Sent from my SM-G955U using Tapatalk
 
dlc95 said:
What happens if you plug it directly into the wall socket?
Click to expand...

Good advice.

Although MarkD51 has great mechanical advice in some above posts, and he is most likely right, I'd first plug the tool into a wall socket like dlc suggested. Just to eliminate the simple & obvious. A bad extension cord can deliver erratic voltage which would also make the machine act as you described.
 
PaulMys said:
Any news on your PC?
Click to expand...
I have not had a chance to use it since then, but I plugged it directly into the wall and it ran smoother. I did not leave it running long, but I have a car to detail next week and I will post an update.

Thank you for following up!

Sent from my SAMSUNG-SM-G935A using Autogeekonline mobile app
 
You must log in or register to reply here.
Back
Top