Impact Wrench Repair/Troubleshooting

Impact Wrench Repair/Troubleshooting - DIY

Impact wrenches are the most common Pneumatic tool a auto mechanic uses. After awhile we start to notice a drop in “Gun”performance . Many companies use inferior parts inside their impacts intentionally. Why pay the tool truck man inflated repair prices. Repair your tools yourself and save that $100 service fee. We will show you How.

ZIW812

The model we will work on today is Zipp's ZIW812 1200 ft-lb 3/4". This impact has been assembly paving breakers without service for the past 3 years. The reason for the service was excessive "hammering" or loss of power
The model we will work on today is Zipp's ZIW812 1200 ft-lb 3/4". This impact has been assembly paving breakers without service for the past 3 years. The reason for the service was excessive "hammering" or loss of power
First thing we will inspect will be the veins. to access the veins we will remove the 4 Allen bolts on the rear of the pistol
First thing we will inspect will be the veins. to access the veins we will remove the 4 Allen bolts on the rear of the pistol
Once the 4 Allen bolts are removed, remove the rear cover to expose the rear bearing housing. The picture shown is from reassembly, I like to use tacky marine grease in all of our air tool service and repair. It doesn't blow out of the exhaust, is very moisture resistant, and lasts as a tacky coating.
Once the 4 Allen bolts are removed, remove the rear cover to expose the rear bearing housing. The picture shown is from reassembly, I like to use tacky marine grease in all of our air tool service and repair. It doesn't blow out of the exhaust, is very moisture resistant, and lasts as a tacky coating.
Once the rear bearing housing is removed you will expose the veins, On our Zipp model there are 6 veins installed. Remove this housing by turning the impact upside down. Depending on the care your tool has received, The veins should fall out very easily. Pictures is a empty wheel with one vein for your reference.
Once the rear bearing housing is removed you will expose the veins, On our Zipp model there are 6 veins installed. Remove this housing by turning the impact upside down. Depending on the care your tool has received, The veins should fall out very easily. Pictures is a empty wheel with one vein for your reference.
The ZIW812's old veins (on left) have a very noticeable wear line down the center of each. This will cause the vein to "shift" as the wheel operates and allow air to bleed through causing a loss of power. This is to be expected after 3 years of no service operation. Note the lack of wear line on the replacement veins (right)
The ZIW812's old veins (on left) have a very noticeable wear line down the center of each. This will cause the vein to "shift" as the wheel operates and allow air to bleed through causing a loss of power. This is to be expected after 3 years of no service operation. Note the lack of wear line on the replacement veins (right)
When reinstalling the veins you want the new ones to move freely in-out of the wheel. As the tool operates the veins are forced away from the center of the wheel. Therefore you do not want to grease this part of the tool. A light thin oil is all that is required here.
When reinstalling the veins you want the new ones to move freely in-out of the wheel. As the tool operates the veins are forced away from the center of the wheel. Therefore you do not want to grease this part of the tool. A light thin oil is all that is required here.
Now is also a good time to clean and wash out the empty rear section of the body. I like to use  a good  solvent cleaner with high evaporation.
Now is also a good time to clean and wash out the empty rear section of the body. I like to use a good solvent cleaner with high evaporation.
Notice the 2 holes at the 6 o clock position. This means that our tool has equal power in both forward and reverse. If the holes were positioned at 5 or 7 oclock it would represent a stronger direction for loosening or tightening.
Notice the 2 holes at the 6 o clock position. This means that our tool has equal power in both forward and reverse. If the holes were positioned at 5 or 7 oclock it would represent a stronger direction for loosening or tightening.
Here is a view of all the parts removed from the rear section of the tool. Your impact model may be different from ours. I recommend taking pictures as you go. It makes reassembly a breeze. For the rear end of the Impact I only grease the open bearings. Everything else gets a thin coat of oil.  Now you can reassemble the rear of the impact  and service the front.
Here is a view of all the parts removed from the rear section of the tool. Your impact model may be different from ours. I recommend taking pictures as you go. It makes reassembly a breeze. For the rear end of the Impact I only grease the open bearings. Everything else gets a thin coat of oil. Now you can reassemble the rear of the impact and service the front.
The front of the Impact is the same process as the rear. Remove the 4 Allen screws and tap the Nose off with a dead blow hammer.
The front of the Impact is the same process as the rear. Remove the 4 Allen screws and tap the Nose off with a dead blow hammer.
Here is the Twin Hammer assembly removed as a whole from the tool.
Here is the Twin Hammer assembly removed as a whole from the tool.
The Twin hammer assembly is held together with 2 dowel pins (bottom right) that will slide right out. Left top is the Anvil. You want to inspect this for excessive wear. Since our model is a Twin Hammer there are 2 (bottom left) hammers. You also want to inspect these as well as the hammer cage (Top middle). Our ZIW812 did not need any of these parts replaced. They were in very good condition.  The front of the impact likes alot of grease. everything was washed and re greased along with the front bearing housing. The tool is ready for reassembly and testing.
The Twin hammer assembly is held together with 2 dowel pins (bottom right) that will slide right out. Left top is the Anvil. You want to inspect this for excessive wear. Since our model is a Twin Hammer there are 2 (bottom left) hammers. You also want to inspect these as well as the hammer cage (Top middle). Our ZIW812 did not need any of these parts replaced. They were in very good condition. The front of the impact likes alot of grease. everything was washed and re greased along with the front bearing housing. The tool is ready for reassembly and testing.

We tested the ZIW812 after it’s service. As expected it was back to top form. A simple vein replacement was all that was required. Since we stock replacement parts for all our tools. Our down time was only minimal. When buying pneumatic tools, Don’t always shop price. look at offered services and the availability of service parts. That $99 impact may cost you more money in down time or service fees than you expected. Like our Facebook page to see videos of our tools in action and please check out our website. www.zippair.com We hope you find this helpful and if you have any questions we wold be glad to help you out.