Part Location Diagram of 901901 DeWALT PISTON STOP AFTER
See part 107 in the diagram
( Grid squares measure 1x1 inch )

PISTON STOP AFTER 901901

Manufactured by:
DeWALT
ERP Number:
ERP18987923
Part Number:
901901
Original Equipment Manufacturer ?
In Stock
Delivers in 3-5 Business Days!

Easy 

15 - 30 mins 

(37 rated repairs) ?

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Product Description

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Genuine Porter Cable replacement part, this item is sold individually. The Piston Bumper is located Cylinder Cap of the nail guns listed below. This part acts as a cushion when the piston/driver retracts back into the cylinder after being fired.

Frequently Purchased Together

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Troubleshooting

This part works with the following brands:
  • Porter Cable
This part works with the following products:
  • Nailer
Part# 901901 replaces these:
901901,

Customer Part Reviews

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4.8
Average Rating (out of 5):
★★★★★
★★★★★
(13 Reviews)
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Customer Repair Instructions

All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part.

Easy 

15 - 30 mins 

(37 rated repairs) ?
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Nailer would not feed. One shot, then nothing but the a mark from the end of the driver - no nail.

Chad from Norman, Oklahoma

35 of 35 people found this instruction helpful.
Difficulty Level:
A Bit Difficult
Total Repair Time:
30 - 60 mins
Parts Used:
901901
I initially thought the problem was a damaged nail driver. Once I disassembled the top of the nailer I found the plastic piston bumper had disintegrated. Note: A properly functioning bumper and spring assembly dampens the recoil of the driver and keeps it high enough in the unit to be in position to strike the next nail. Without the b umper intact the driver snaps down below the nails and will not pick them up on the next trigger pull. Other than not picking up a nail, everything else appears to work properly. The youtube video produced by ereplacementparts (the one that addresses an overhaul) was all I needed to see how to fix it. I used the air compressor to blow out the 10,000 some odd pieces of piston bumper - it was all over the place. All of my o rings look intact, but it probably would have been worth the time to replace them. We\'ll see how that goes. I did lube them all with o ring silicone when I put it back together. Worked great on the test run.
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Nailer would not draw all the way back to allow another nail in the chamber

Travis from Sevierville, Tennessee

13 of 13 people found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
30 - 60 mins
Tools:
Nutdriver, Wrench set
Parts Used:
901901
I removed the top cap of the nail gun and saw the broken pieces of the piston bumper. I removed all plastic debris from upper area. Then replaced piston bumper, worked like charm. all my seals, o-rings and gaskets were good as I had oiled religiously over the years. All good
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The framing nailer stopped working

Roger from McCordsville, Indiana

7 of 7 people found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
15 - 30 mins
Parts Used:
901901, 903788
Had to disassemble and inspect. Found piston bumper had broken up and damaged the piston seals. Thoroughly cleaned all internal parts as per instructions and install new seals the come with the Overhaul Kit.. I had watched the video that was on your site and found Overhaul a breeze.
Thanks R.G.
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Piston bumper disintegration

Keith from Cromwell, Minnesota

5 of 5 people found this instruction helpful.
Difficulty Level:
A Bit Difficult
Total Repair Time:
15 - 30 mins
Tools:
Pliers
Parts Used:
901901
1. Removed 4 Allen screws on head
2. Remove piston and collar
3. Use pliers to remove what was left of piston bumper
4. Use air and parts cleaner to remove all pieces of disintegrated piston bumper
5. Install in bumper
6. Apply lube to the o-rings
8. Install head torque bolts
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The piston bumper was smashed into a million pieces.

John from Charleston, Mississippi

2 of 2 people found this instruction helpful.
Difficulty Level:
A Bit Difficult
Total Repair Time:
15 - 30 mins
Parts Used:
901901
Watched your U tube movie on how to repair. That showed me how to do the job. I have never had a nailer apart before. Took nailer apart. The nailer did not need the piston or nailing slide taken out as shown on the movie. It did need to be banged on a block of wood to remove parts in the top (as shown in movie). Removed top section from n ailer. Removed all particles of busted bumper. Reassembled with new bumper, applied air pressure, tested on a 2x4 block of wood. It worked just fine.
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Broken bumper

reynaldo from mcallen , Texas

2 of 2 people found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
15 - 30 mins
Tools:
Nutdriver, Screw drivers
Parts Used:
901901
Remove the screws from the top cap. Remove the broken bumper and all of the pieces of it in the gun. Replace the bumper and oil the interior of the gun. The screw the top cap back on.
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Air leaking out of top

robert from Clayton, North Carolina

2 of 2 people found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
15 - 30 mins
Parts Used:
901901, 886108
I used the allen wrench that came with the nailer to remove the cap.
I removed the broken piston bumper
I removed the valve seal
I cleaned the internal area of the gun completely & oiled it
I installed the new parts
I then screwed the cap back on







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Nailer was slow to recover after power stroke. It drove the nail fine and then would leak air for a bit before it fully recovered.

Robert from TEMPE, Arizona

1 person found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
Less than 15 mins
Parts Used:
901901
1. Removed the tool from the air supply.
2. Removed the four cap screws that hold on the top cover.
3. Removed the air chamber seal piston, spring, and washer from the top cover. Pay attention to the order of parts as you remove them.
4. Removed the shattered piston bumper.
5. Cleaned up the interior of the top co ver and the seal piston.
6. Installed the new piston bumper. It just pushes into place.
7. Inserted the air chamber seal piston, spring, and washer back into the top cover.
8. Reattached the top cover and tightened the four cap screws that hold it in place.
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Piston Bumper was old and several pieces. Nailer 20 years old!!!!

Mark from Piedmont, Oklahoma

1 person found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
15 - 30 mins
Parts Used:
901901, 890725, 887249
Disassembled piston unit and installed new piston Bumper. Replaced trigger pin retainer and re-assembled unit back and installed nose cushion and unit is back in business. Thanks
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Piston bumper deteriorated inside the gun

Matt from Alpharetta , Georgia

1 person found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
30 - 60 mins
Repair was easy and cost effective. All I did was watch the video first to see if I wanted to tackle the project. When it was over discovered there really isn\'t a lot of parts inside to keep me from trying it. So, I disassembled the nailer and found the source- broken piston bumper. I could see all kinds of plastic pieces scattered throu ghout the internal workings of the gun. After a good cleaning and a check of all the o-rings, the top portion of the nailer would have to be replaced. Next, I ordered the parts from the website which was simple and easy- in fact I also found a part to my Porter Cable sander as well. After a few short days the parts arrived and I put the gun back together, plugged it into the compressor and tried it out. \"P-ka,\" the nailer was once again making that sweet sound that my wife can\'t stand.

Now if I had to buy the complete overhaul kit I\'m not too sure I would have fixed the nailer. Reason being, the big box stores are always having a sale and a new one could be found for 30-50 dollars more with a one year warranty. Unless, I already had an abundance of nails that were specific to the old nailer then I would fix the old one.

Good Luck with your project and may the force be with you!
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