( Grid squares measure 1x1 inch )

PISTON STOP 904685

Manufactured by:: DeWALT
ERP Number:: ERP18987979
Part Number:: 904685

$38.70

★★★★★

11 Reviews

Delivers in 3-5 Business Days!

Easy

15 - 30 mins

(45 rated repairs) ?

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Description Frequently Purchased Together Troubleshooting Reviews Questions & Answers Repair Instructions Model Cross Reference

Product Description

This piston stop is for nailers. The piston stop provides a cushion for the piston. Wear work gloves to protect your hands when installing this part.

Frequently Purchased Together

SEAL

★★★★★

(32)

$16.85

O-RING

★★★★★

(9)

$6.02

Minimum Quantity of 2 required

HOUSING CAP

★★★★★

(17)

$51.83

O-RING (29.5 X 2 (S3

★★★★★

(5)

$9.13

Minimum Quantity of 2 required

★★★★★

(5)

$13.02

PISTON RING

★★★★★

(4)

$17.25

PAD

★★★★★

(5)

$14.63

O-RING (31 X 2 (2031

★★★★★

(1)

$10.22

GASKET

★★★★★

(1)

$24.98

PISTON-HEAD VALVE

$26.33

WASHER-BEARING

$6.16

Minimum Quantity of 2 required

Troubleshooting

This part works with the following brands:

Porter Cable

This part works with the following products:

Nailer

Part# 904685 replaces these:

904685,

★

Customer Part Reviews

4.9

Average Rating (out of 5):

★★★★★

(11 Reviews)

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★★★★★

Works great!

My nail gun is sitting in my storage for years, thinking about throwing it because its not working. But when i heard about ereplacementparts.com, and ordered the part, it brings back the life on my tool. I should have known that earlier before i bought a new one. Thank you very much. Still have some tools that needs some repair. That will be next.

David - July 5, 2019

Verified Purchase

★★★★★

Great service. Parts arrived on time!

See above.

Guest - September 11, 2019

Verified Purchase

★★★★★

Easy and necessary repair

I had a rebuild kit for a long time and finally got around to doing the repair. I opened the top of the gun and the piston stop was rotted and in pieces! No Wonder the gun did not work right. This piece was not in the "official" rebuild kit so I got it from E-Replacements and it went right in and now the tool works perfectly. Easy to do and simply essential!

Guest - October 15, 2019

Verified Purchase

★★★★★

Exact replacement

Part was received early and in great shape. Was exactly as specified and shown in product picture

Roger - October 25, 2019

Verified Purchase

★★★★★

Quick service

I needed a small part, was notified they were out of stock. The caller told me where I could go to get my tool repaired. I went there and was told that repair would be almost the cost of a new tool. When I got home the part from eReplacement was in the mailbox.

Guest - June 8, 2020

Verified Purchase

★★★★★

Piston Stop for nail gun.

Great site to buy from. Received the right part in a timely manner. Will definitely recommend this site.

Guest - March 29, 2021

Verified Purchase

★★★★★

Piston stop

So far so good. We’ll see after using for a while:

GABRIEL - April 29, 2021

Verified Purchase

★★★★★

Nailer works like newe.

Always confident in dealing with ereplacement that I will get what I need.

Peter - January 17, 2023

Verified Purchase

★★★★★

Easy repair.

Perfect part to get my nail gun back to operating.

Joel - March 25, 2023

Verified Purchase

★★★★★

Great company

Correct part. Shipped quick. Recommend

Guest - May 5, 2023

Verified Purchase

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Questions & Answers

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We have a dedicated staff with decades of collective experience in helping customers just like you purchase parts to repair their products.

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How to replace part #904685

Robert For model number FN250B - November 8, 2023

Hi Robert, Thank you for writing. Here are some steps a previous customer has posted." 1. Removed top cover 2 Removed shattered piston stop and cleaned out all of the bits and pieces 3. Reassembled and tested" We hope this helps!

eReplacementParts Team

November 8, 2023

1 person found this helpful.

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Nailer is leaking air out of the back/top. What parts do I need to replace to fix it?

Marcus For model number FN250B - December 3, 2023

Hello Marcus, Thank you for your inquiry. We would recommend checking the head valve seal, piston stop, and o-rings. We have also included a link to our repair article on troubleshooting this issue for your nailer. Good luck with your repair. https://www.ereplacementparts.com/repair-center/power-tool/nailer/leaks-air-from-top/

eReplacementParts Team

December 3, 2023

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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

(45 rated repairs) ?

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Rebuild head valve

Joseph from Riverview, Florida

20 of 20 people found this instruction helpful.

Difficulty Level:: Easy
Total Repair Time:: 15 - 30 mins
Tools:: Pliers, Screw drivers
Parts Used:: 904689, 904685

The piston stop had hardened and crumbled. I removed the top of the gun by removing the four hex screws. Then the top of the gun comes off and you can take out the piston stop. I also replaced the head valve seal because it is made out of the same kind of plastic. Pretty easy and now the gun works again.

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Urethane Piston stop crumbled

Cody from Burleson, Texas

19 of 19 people found this instruction helpful.

Difficulty Level:: Easy
Total Repair Time:: 15 - 30 mins
Parts Used:: 904685, 897359, 890725

Super easy, E replacements online video walked me though it. The repair it showed was different than mine, but the disassembly steps showed me how to take apart the gun in order to diagnose the issue.

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Would not drive nails. Driver rod would not fully retract preventing a new nail from loading

robert from slidell, Louisiana

6 of 6 people found this instruction helpful.

Difficulty Level:: A Bit Difficult
Total Repair Time:: 15 - 30 mins
Parts Used:: 904685

1. Removed top cover
2 Removed shattered piston stop and cleaned out all of the bits and pieces
3. Reassembled and tested
4..OK

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The gun would not nail and a lot of air came out of the top

Cynthia from Wimberley, Texas

4 of 4 people found this instruction helpful.

Difficulty Level:: A Bit Difficult
Total Repair Time:: 15 - 30 mins
Parts Used:: 904689, 904685

Removed the cylinder cap from the top of the gun. I then noticed the broken piston stop and loose head seal. I removed all of the pieces of the broken piston stop. and replaced the head seal. Thoroughly cleaned the inside and oiled it. It fires nails like it new.

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Worn out seals and busted piston bumper

Tim from Hoolehua, Hawaii

4 of 4 people found this instruction helpful.

Difficulty Level:: Easy
Total Repair Time:: Less than 15 mins
Parts Used:: 904725, 904685, 886119

Follow video that was provided by ereplacement parts and then go from there.

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Leaking air at rop

Mark from OVIEDO, Florida

3 of 3 people found this instruction helpful.

Difficulty Level:: Easy
Total Repair Time:: Less than 15 mins
Tools:: Wrench set
Parts Used:: 904685, 890725

Remover allen head screws.
Gently, lifted head from body careful not to damage gasket.
Removed damaged parts and replaced.

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Non-metalic internal parts disintigrated

Michael from Port Orange, Florida

1 person found this instruction helpful.

Difficulty Level:: A Bit Difficult
Total Repair Time:: 15 - 30 mins
Parts Used:: 904689, 904685

1. Disassembled Nailer
2. Removed debris, residue and broken parts
3. Installed new parts.
4. Applied pressurized air and tested for correct operation.
5. Test failed. Nailer drove one nail, but did not reset. All air pressure lost.
6. Disassembled Nailer again.
7. Installed parts correctly.
8. ... Read more

Read less

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Nailer leaked air and would not fire nails

Michael from GAINESVILLE, Florida

1 person found this instruction helpful.

Difficulty Level:: Easy
Total Repair Time:: 15 - 30 mins
Parts Used:: 904685

Replaced part (which had totally degraded into several pieces) and put back together (second time correctly). Nailer worked great after that.

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air finish nailer leaking air from top of gun

William from Alexandria, Virginia

1 person found this instruction helpful.

Difficulty Level:: Easy
Total Repair Time:: 15 - 30 mins
Tools:: Pliers
Parts Used:: 904689, 904685

1) Open top
2) Remove broken / deteriorated parts, replace with new parts. Only hard part was the old piston stop needed needle-nose pliers to pull out.
3) Close top

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Nail gun would not fire nails

Rodney from Richardson, Texas

1 person found this instruction helpful.

Difficulty Level:: A Bit Difficult
Total Repair Time:: 15 - 30 mins
Parts Used:: 904689, 904685

Removed the screws from the top cover
Removed the defective stop and seal and cleaned the interior of the gun
Installed the new parts
Replace the top cover

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Model Cross Reference

This part works with the following models:

ERP Number: ERP18987979
Manufacturer Part Number: 904685

Brand	Model Number	Description
Porter Cable	FN250B	Nailer - 16 Gauge Finish Nailer
Porter Cable	FN251	Nailer - 53444