Photo Guide to Installing E-Z-On Heavy Duty Tether Anchors (PIC HEAVY)


Active member
Following the thread from cmm7 regarding installing the E-Z-On 86Y harness, I thought it would be helpful to post a kind of guide to the process of installing the Heavy Duty Tether Anchors from E-Z-On.

Below are my notes and photos from the recent installation of the E-Z-On Heavy Duty Tether Anchors. I very much hope these will be useful and that they are understandable. I will try to explain things clearly however if there are any questions, just let me know and I’ll do my best to answer them.

I shall not cover the selection of a suitable location for the heavy duty tether anchors in very much detail because firstly, most vehicles will already have a pre-determined position (either through some kind of markings or the existence of factory fitted tether anchors) and secondly, if a self-determined position must be chosen, the discussion of such probably deserves a thread by itself.

I will try to cover the process in reasonable depth and I hope the level of detail will not “deter” anyone (for want of a better word). The process is not complicated and will take no more than 15 to 20 minutes to complete.

To complete the installation, you will need the following tools:


• Pencil/Pen
• Hammer
• Centre punch (or big nail)
• Some standard general purpose/home use oil
• 1/2 inch drill bit (or ideally a 17/32 or 13mm drill bit)
• Electric drill
• A deep socket to match the nut in the anchor kit
• A spanner to match the bolt in the anchor kit
• Torque Wrench
• Silicone or PU Sealant (of the automotive type)
• Some tissue paper or a towel


• Blanket or large towel
• Rule (or any short straight edge)
• 5/32 and 11/32 inch drill bits or similar
• A round metal file
• Some “Threadlocker” glue
• Masking tape (or any tape you can write on satisfactorily)


Having chosen the location for the anchor, protect any nearby area of the interior such as carpet, trim, bulbs etc, by covering them with a towel or a blanket. This is not essential but does make the job easier and more relaxed. I took out the removable boot floor carpet and also unclipped the rear boot lip trim panel - this way I wouldn’t damage anything aesthetic if I knocked it with some tools.

The boot (trunk I should say!):

Any with the carpet and trim removed:

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Active member

With the necessary areas protected, test fit the anchor in the chosen location:

Be sure to check carefully before marking anything that you can work safely in the area. For example, will the drill chuck fit past any protruding brackets or metal? Is there adequate access to both sides of the metal panel to allow for the use of spanners and sockets? When you are sure everything is ok, remove the tether anchor and cover the area underneath it with masking tape. Place the anchor back into the desired location:

Holding the anchor firmly with one hand, use a pencil or pen to clearly mark where the hole is to be drilled. Make the mark as clear as possible:

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Active member

Once the marking is complete, use a ruler to carefully locate the centre of the circular mark as accurately as possible. You don’t have to do this – you could just mark the middle of the circle by eye, but if the hole is to be drilled in a tight area, accuracy could prove essential. For example, if you established from your pre-hole marking assessment earlier, that the fit of the socket or spanner will be close, a hole which is 1/12 of inch off centre could mean that the spanner or socket will no longer fit, so it is always worth being as thorough as you can be.

With the centre of the marking located, use the centre punch (or large nail) and hammer to make a clear indentation on the centre mark. If you are able to securely place a block of wood behind the area to be hit, do so. The technique here is quite important. The centre punch may spring up slightly when struck (this is quite normal), so hold it firmly and give it two strong hard hits with the hammer. Don't be afraid to hit quite hard!

Once you can see a clear, small and neat dent on the centre mark, remove the masking tape. You should now have a good location to start drilling:

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Active member

With a good starting location, you can prepare to start drilling. It is strongly advisable to drill a small hole to begin with and then slowly enlarge the hole using progressively larger drill bits. The hole could be drilled in one go but it will take a very long time, and will more than likely destroy the drill bit. I used a 4mm drill to begin with, then enlarged the hole to 8mm and completed the drilling with a 12mm bit:

Before drilling, be aware that the edges of the hole, as well as the drill bit itself, will become VERY hot. Remember to wait a few minutes to change drill bits as you’ll burn your hands if you try to change the bit immediately after drilling.

Once you are ready to start drilling, cover the centre punched mark with some oil. This will help with two things. Firstly it will keep the drill from becoming too hot too quickly and will therefore cut much better. Secondly, it will help catch the majority of the filings and waste which are produced by the drilling.

It is important to remember that the metal you are drilling into is very solid so apply firm pressure to the drill and if the speed setting of the drill can be varied, set it to be quite slow. Drilling with a high speed through metal will cause heat to build up rapidly and you may damage or blunt the drill bit.

The mark prepared for drilling:

The progressively larger holes:

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Active member

It is not essential to file the edges of the hole, however if a round file is available, I recommend doing so as the bolt will slide through more easily. I filed the hole from both above and below:

After wiping away the excess oil and filings with some tissue, the anchor can be test fitted.

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Active member

If the test fit is successful, then try reassembling any trim parts and carpet to check if anything will foul the tether anchor. I had to cut a very small piece of plastic trim away to make sure the anchor was fully accessible:

This is unlikely in most vehicles, but it is always worth a check. Once you are confident everything will fit, then the final step is actually do up the nut and bolt properly. Although a seemingly simple step, there are couple of things to watch out for. The bolt should be done up to the correct torque setting and this varies from bolt to bolt and from scenario to scenario.

When I installed the anchors, the bolt supplied by E-Z-On was a 7/16” SAE grade 5 bolt with 20 threads per inch (tpi). Although I doubt this has changed, please consult this table to obtain the correct torque setting and if in any doubt, contact E-Z-On. In my situation, the required torque setting was 55 lbs/sq. inch. You can identify the bolt specification using the images of the bolt head markings above the table.

Having obtained the correct torque value, apply some silicone or PU sealant to one side of the washer. A reasonable but not excessive amount should be used:

With both the washer and the torque wrench prepared, the final step is to apply some “Threadlocker” to the bolt. This is by no means essential but will guarantee the bolt will not loosen. Only apply a small amount of the “Threadlocker” as it moves through the threads when the nut and bolt are tightened.

If using “Threadlocker”, there is no need to move overly quickly through the process as it will not set until the air is squeezed out – e.g. the nut and bolt are tightened.

When you are ready to finally secure the nut and bolt, first push the washer onto the underside of the metal, aligning the drilled hole and the washer hole as best as possible. The sealant will hold it place and you will not have to worry about it falling off while you are using the spanner and torque wrench. Place the anchor over the hole, slide the bolt through and secure it using the torque wrench and spanner. Ensure the washers are in the order as specified in the E-Z-On instructions.

When tightened properly, there should be some sealant leaking outward from the washer. This shows the bolt has been tightened properly:

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Active member

Once everything is secure, reinstall the trim and carpet if any was removed, and the process is complete!

I hope this is of some help and if there are any questions, please don’t hesitate to ask me.

(The pictures seem quite large, so if people would like them resized, just let me know!)

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New member
Thanks so much for putting these up for me! I am expecting the harness Monday or Tuesday and will show these to my boyfriend who is putting it in for me.

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