Another MaxJax Anchor Question

[AO928]

Did a search but couldn't locate the an answer to my specific question.

So I got my MaxJax about a year and a half ago and I was using it diligently. But because my garage is rather shallow I didn't have much choice where to locate it. I had to locate it near the relief cuts made in the slab. I knew it was a gamble and it bit my ***. The slab cracked where the anchors were and a few of the anchors would no longer hold torque! Yikes!

So I had a section of the slab cut, dug, and re-poured. I now have a large 3' x 13' x 12" footing that is keyed under the slab with rebar. I only have a picture of the initial cut and dig.

The concrete was poured on November 27th. I know it is recommended that I wait at least 28 days before using a lift, but I thought I could at lease drill the holes and set the anchors for the MaxJax.

Here's my main question.

I bought a fresh set of Wej-it anchors. What's the best way to ensure the anchors bite and set in the new concrete? I had a couple that did not set last time and had to punch them through and install epoxy anchors ($$$). With the footing/base now 12" deep, I cannot punch them through if I have a problem, so I need to make sure they set right the first time.

One thought I had was to use some epoxy on the wejit anchors themselves when setting them. Then wait a day or two and check to make sure they hold 90ftlbs of torque.

Other suggestions or opinions?

Thanks in advance.

 

[readhead]

Draw them up tight with a proper washer before you install the lift. The holes in the lift are probably oversized and the anchors will not have anything solid to hold them down when you tighten them.

 

[AO928]

Do you mean to put a washer between the lift and the anchor so they cannot come proud of the surface?

 

[readhead]

No. Mark the holes, move the lift and drill the holes. You can also drill through the base plate and then move the lift. Put the anchor in the hole and tighten the bolt to draw up the anchor. Remove the bolts and replace the lift. Now the anchor is tight in the hole and you should be able to place the bolts and tighten them.

 

[AO928]

No. Mark the holes, move the lift and drill the holes. You can also drill through the base plate and then move the lift. Put the anchor in the hole and tighten the bolt to draw up the anchor. Remove the bolts and replace the lift. Now the anchor is tight in the hole and you should be able to place the bolts and tighten them.

Well then, i think you're basically telling me to follow the directions. The problem is I did that last time and a few of the wejit anchors did not bite. I need a fool-proof method for making sure they work this time.

 

[readhead]

Is the concrete poured yet? If not have some threaded embeds made to pour into the concrete. A new concrete bit for the drill will help also. Are you going to move the lift? If not use wedge anchors instead of drop-ins. They have more bite.

 

[readhead]

I went back and saw that it is poured already. Like I mentioned before if you are not going to move it use 6" wedge anchors and it should tighten right up. You could also use threaded anchors and epoxy. Drill the hole 1/8" over the rod size and make sure the hole is very clean. If you ever do move the lift just cut the bolts flush with the concrete.

 

[97dynaglide]

I'd go with epoxy anchors, simply because if even one of the Wej-it's doesn't seat, you have no way to remove it or drive it thru the bottom. The only other option would be to try to remove it by chiseling and then redrill for a larger anchor and bolt.

I'm having a problem with 4 of the 5 anchors on one of my columns, they didn't seat until they were over 1/4" up above the concrete.
Looking at the thickness of my slab after driving the failed anchors down, I can see that I'm just shy of 3 3/4" thick. I'm cutting and pouring a 4x4 slab 8" thick and using the epoxy ones anchors.

 

[AO928]

I'd go with epoxy anchors, simply because if even one of the Wej-it's doesn't seat, you have no way to remove it or drive it thru the bottom. The only other option would be to try to remove it by chiseling and then redrill for a larger anchor and bolt.

I'm having a problem with 4 of the 5 anchors on one of my columns, they didn't seat until they were over 1/4" up above the concrete.
Looking at the thickness of my slab after driving the failed anchors down, I can see that I'm just shy of 3 3/4" thick. I'm cutting and pouring a 4x4 slab 8" thick and using the epoxy ones anchors.

That's my fear.

How about using epoxy on the Wejit anchors and the setting them per the instructions (so they are nearly flush with the surface). This should provide double assurance that the anchors don't move when anchoring down the lift posts.

Any drawbacks to this approach?

 

[97dynaglide]

The only drawback I can see is that the wejit's aren't made for the epoxy method. The epoxy anchors have 4 'ribs' on them that will be encased in the epoxy.

Since you have to drill almost 4.5", why not just go the extra 1.5" and use the epoxy ones. I know they're not cheap, but I think that it is the surest way to go with a 12" thick slab.

 

[readhead]

You have to drill the exact size hole for the drop-ins which does not leave any room for epoxy. We don't like drop-in anchors for this very reason. If you want something removable look at Titan screws. They are like a lag for concrete. Redhead calls theirs LDT.

 

[regguy1]

I copied and pasted this from another post I made, I had some issues with the anchor installation this might be of help during your install:

(I think Dannmar might have corrected /revised their instruction since I wrote this**)
Here's the update, I've got the lift installed and running. It looks like a nice unit. The power unit is quieter than I thought it would be. Installation was straight forward.

I think setting of the anchors is the most critical part of the installation procedure. A couple of things I'll mention from my experience of this one installation. Let me say this first, I'm not a pro lift installer and the following are my opinions only. Drill the holes as per instructions. Do a through job of cleaning the holes. Even though the supplied anchors (Wej-It PD58) are not specificly epoxy style units I'd recommend using a good quality epoxy for additional integrity of anchor bond to concrete. I coated the hole and the exterior of anchors before driving them in. Drive them the 5/8" below concrete as instructions call for, I wouldn't go less.

Now thread the sacraficial bolt with washer and nut finger tight into the anchor, hold the bolt head (you do not want the anchor to rotate in the hole) and tighten the nut to set the anchor, the lift instruction booklet says tighen until anchor is flush with the concrete surface.....The instructions that came in the box of anchors say no more than 4 turns for the 5/8" bolts size. I found that at about 3 turns I could feel the anchors bite hard into the concrete even though they were still 1/8" -3/16" below the surface of floor. I think it's fine (and even preferable) to leave them slightly down because when you tighten the bolts to the base plate if the anchor is not holding properly you'll realize it when torquing the bolts, but with the anchor flush it can contact the bottom of the base plate and feel tight even though not fully anchored in the hole.

**Page 13 step 14 of the lift installation manual tells you to install anchor bolts to base plate and tighten 3 to 3 3/4 turns. I believe this is in error, the anchors have already been set with the bolt and nut procedure. These bolts should be torqued betweem 70-95 Ft Lbs according to Wej-it (95) and Dannmar (70).

I found it impossible to get 3+ turns after anchors were set and it caused a couple anchors to pull up (perhaps they rotated in the hole and lost grip ?) and I have to replace them.

 

[skamp]

If I repoured a section like you there would be no way I would use the wedge anchor. I would go straight for the epoxy anchor and be done with it.

Steve

 

[AO928]

Thanks everyone. And thank regguy, you answered my question exactly. I will update as soon as I have something to post.

 

[sidwin]

has anyone noticed that epoxy anchors require 6.5 inches to depth?

and they are also out of stock and discontinued from wej-it.

I had 3 spin on me and i removed them and then put new ones back down and this time i coated the outside of them with epoxy and then some in the hole. hopefully they will hold. i'm worried they won't. one post all 5 went down fine and one post only 2.

thanks,
Sid

 

[Jyuma]

I realize this is a very old thread, but given that I only just bought my MaxJax there should be no surprise that I encountered the same issues with using/installing the Wej-It anchors. that so many others did.

First let me say that Wej-It anchors are very likely well designed and built... the only problem is they don't work about half the time if you install them following the instructions to the letter. Fortunately for me I have a very large garage so having to drill new holes and try again... 3 times... only cost me my time and about fifty bucks for new anchors. My slab is thick so I never did get to drill all the way through, otherwise I would have pounded the anchors that didn't grab through the slab and put new ones in using epoxy. Yes you can use epoxy with the Wej-It anchors supplied with the MaxJax.

Disclaimer: I am not an expert, I am a regular user like you guys but if it required an expert to install these anchors then the MaxJax instructions should say so and be done with it. That being said... after 2 failed attempts... 20 holes drilled to 4.5" deep and sacrificial bolts hammering in anchors to 5/8" below the surface and then tightened to the point where they "appear" to grab, I have become an expert in what not to do. Don't do that.

I noticed the same thing about every anchor that failed to grab... it was absolutely impossible to get them out. Huh? Won't grab but won't come out either? How is that possible? Well, they do eventually grab but the problem is they're sticking half an inch above the surface before they grab for good.

My solution (that worked) drill the holes deeper and set the anchor all the way to the bottom of the hole. I drilled mine almost 6" deep. That way, instead of having only 1/2" to hope and pray for the anchor to grab, I got 2" to hope and pray for the anchor to grab. Now before you start complaining that the bolts provided are only 2" long, let me direct you to the hardware isle at Home Depot where they sell 5/8 -11 bolts in sizes up to at least 6" (prolly more). I bought 10 3" 5/8 -11 bolts from the Borg but you can buy whatever size you need.

I followed the instructions for the I initial "set" of the anchors... but I started with the top of the anchor now about 1 1/2" below the surface rather than 5/8". The result... every anchor set perfectly and my 3" 5/8-11 bolts were just the right size. Not too short and not too long. I was able to torque the bolts to 90 fp without them pulling out of the concrete.

As a test I clamped a 6 foot level to the back of the posts and lifted a 4000 lb car to full height with do detectable lean.

I should mention that I'm not fond of the shim instructions they give you for leveling the posts... no more than 1/4" at any one point. Quite frankly any garage floor that doesn't have a 4" slope back to front for water run-off wasn't poured right to begin with... so I took my trusty angle grinder with a diamond wheel and leveled the concrete under the posts footprint before installing them. Still need a shim or 2 but not the 4 and 5 needed before leveling.

Hope this helps somebody... it would have saved me a ton of work if I knew then what I know now.

 

[Mr onetwo]

This is precisely why it is best to get the epoxy anchor kit when you buy the lift and ditch the wedge anchors.

 

[alberto]

........let me direct you to the hardware isle at Home Depot where they sell 5/8 -11 bolts in sizes up to at least 6" (prolly more).

I really hope you bought grade 8 bolts for this from them and didn't buy the run of the mill bolts they sell.

 

[Jyuma]

I really hope you bought grade 8 bolts for this from them and didn't buy the run of the mill bolts they sell.

Good question: No, I used the regular Grade 2 bolts that HD sells. Before doing so I checked the specs on grade 2. The minimum tensile strength of a Grade 2 is 74,000 psi compared to 120,000 for the Grade 5's that were supplied with my lift.

I figured that 5 bolts with a minimum tensile strength of 74,000 psi each should be good enough for a 4000 lb load. Am I wrong? Easy enough to change them if that's what should be done.

 

[alberto]

If the manufacturer of the anchors supplied grade 5 bolts, I would definitely use that and nothing less. The way you installed them also may have changed the stresses transferred to the bolt (one could argue whether it's significant or not), so I'd go grade 8 bolts if it were me.

 

[Coasterbuilder]

Good question: No, I used the regular Grade 2 bolts that HD sells. Before doing so I checked the specs on grade 2. The minimum tensile strength of a Grade 2 is 74,000 psi compared to 120,000 for the Grade 5's that were supplied with my lift.

I figured that 5 bolts with a minimum tensile strength of 74,000 psi each should be good enough for a 4000 lb load. Am I wrong? Easy enough to change them if that's what should be done.

Its really not as simple as that, that's why they make engineers. Did you consider proof load vs. tensile strength? Fine thread vs coarse thread? Preload tension on the bolt when you tightened the bolt? Moment reaction when the top of that lift post deflects like a giant lever arm- with a truck on top? What did you use for a safety factor? Tensile/ proof load is great. What about shear?

MaxJax paid an engineer to think about this and came up with a cheap grade 5 bolt so you could worry about other things.

 

[Jason280]

This is precisely why it is best to get the epoxy anchor kit when you buy the lift and ditch the wedge anchors.

This can't be posted enough.

 

[superskaterxes]

if you have ever installed something into concrete epoxy you will instantly know why everyone is saying to switch to it. You could put all-thread in a hole with epoxy and it would be stronger than those stupid wedge anchors.

also if your looking for better bolts go to mcmaster. I wouldent use anything less than grade 8, they are super cheap and you can get exactly the size you need.

 

[Jyuma]

Its really not as simple as that, that's why they make engineers. Did you consider proof load vs. tensile strength? Fine thread vs coarse thread? Preload tension on the bolt when you tightened the bolt? Moment reaction when the top of that lift post deflects like a giant lever arm- with a truck on top? What did you use for a safety factor? Tensile/ proof load is great. What about shear?

MaxJax paid an engineer to think about this and came up with a cheap grade 5 bolt so you could worry about other things.

All good points. I have no reason not to change them.

 

[rburke65]

There are lots of companies, people n others that use wedge anchors and they have purported perfectly well.

 

[NewShockerGuy]

OLD thread but want to ask.

I just had an anchor start lifting up. I thought it was odd because I kept using my torque wrench set at 90ft lbs and the bolt kept spinning and the washer started cupping... I move the lift and see that the anchor that was once below the concrete is now flush with the concrete... I put some washers on and then was able to lift the anchor out 5mm... I hammered it down and through the concrete.

I just put in a new wejit anchor. IF this fails I am using epoxy ones since I have 10 of them left over from years ago... two problems I have. The concrete below I can see a space... so if I pour epoxy onto the new anchor it will just run out the bottom...

Two.. what is the correct spec to torque the bolts. I always have done it 90ft lbs... but now I wonder is that too much?

70-95 Ft Lbs according to Wej-it (95) and Dannmar (70)

What is everyone using?

Thanks,
-Nigel

 

[NewShockerGuy]

if you have ever installed something into concrete epoxy you will instantly know why everyone is saying to switch to it. You could put all-thread in a hole with epoxy and it would be stronger than those stupid wedge anchors.

also if your looking for better bolts go to mcmaster. I wouldent use anything less than grade 8, they are super cheap and you can get exactly the size you need.

Would you by chance happen to know the exact bolts/washers you used? I want to change all mine out now since the washers are all cupped....

Thanks,
-Nigel

 

[NewShockerGuy]

OLD thread but want to ask.

I just had an anchor start lifting up. I thought it was odd because I kept using my torque wrench set at 90ft lbs and the bolt kept spinning and the washer started cupping... I move the lift and see that the anchor that was once below the concrete is now flush with the concrete... I put some washers on and then was able to lift the anchor out 5mm... I hammered it down and through the concrete.

I just put in a new wejit anchor. IF this fails I am using epoxy ones since I have 10 of them left over from years ago... two problems I have. The concrete below I can see a space... so if I pour epoxy onto the new anchor it will just run out the bottom...

Two.. what is the correct spec to torque the bolts. I always have done it 90ft lbs... but now I wonder is that too much?

70-95 Ft Lbs according to Wej-it (95) and Dannmar (70)

What is everyone using?

Thanks,
-Nigel

Update: The replacement anchor that I switched out over a year ago started lifting again. It was flush with the concrete. I spent 30 minutes hammering it through the concrete and just got my tube of epoxy again. I didn't realize the first tube I had was a shelf life of a year so it was rock solid. I'm going to epoxy that new anchor in now. I bought 10 epoxy anchors years ago and used 3 or 4... I am HALF tempted to completely hammer the other anchors in and use the epoxy but honestly the other side is fine. Zero movement in anchors. ... So if it's held for 5-6 years now I guess we are fine.

-Nigel

 

[NewShockerGuy]

Tested the lift again today with the newly expoxied anchor. Zero issues. I however upon lowering the car and removing the lift noticed a wedge anchor lifted somewhat. I took the bolt screwed it in and gave a slight wack and the anchor dropped... smfh. Ordered another epoxy tube and will then replace the anchor with an epoxy one. These damn wedge it anchors are horrible. I torqued it slightly more this time I think 80 ft lbs, but that's enough along with the weight of the car to pull it up, I'm done with it. I'm going to test all other ones and if they have shifted or moved they are getting pounded through the floor and epoxy ones will replace them.

I still haven't fond a GO TO answer on torque. MaxJax directions state UP to 95ft lbs of torque. I think I normally do it to 75ish give or take, but I just would hate to keep having to torque them and then they lift because I am doing it too high?

-Nigel

 

[curiousB]

Tapping a wedge anchor back to flush releases the wedge mechanism. Next time an anchor creeps up slightly just grind the top of the anchor back to flush. Loosing 1-2 threads will not have a major impact to holding strength.


Sent from my iPhone using Tapatalk