When do you replace the Shear Pin

[bigleo48]

OK...before I get the "when it's broken" smart answers, hear me out.

I seem to be replacing a M5 shear pin every couple of weeks. I use to replace them when they broke, but that usually happened at the least opportune time and typically would tick the customer off...especially when it broke without touching the arch (likely weakened by a previous hit).

So now I replace them after two minor hits and I'm contemplating changing them every couple of weeks regardless. It takes me 30 seconds to change one now, but I'm just trying to be proactive. What do you guys do?

Also, the pins are stainless and cost $6 pop. I'm not trying to be cheap, but why do I need stainless for a part that last no more than a month!? Do any of you guys make you're own?

Thanks in advance...BigLeo

 

[raisetheprice]

A good way to tell if it's worn is to try and remove it. If it comes out clean and easy, it's good. If it's hard to pull out...replace. Sometimes if it's worn enough I have to actually break it to get it out. On the LW4000 if it becomes weak, many times the arch will block the front eyes if you have the extra padding down low. With M5 I wouldn't replace until broken as you don't have to worry about blocking any eyes.

 

[ScottV]

I do the same test as RTP. If it is bent, I change them. If it isnt, they get changed once a month, or every other PM (since I do those in 2 week intervals).

 

[MEP001]

You could contact a local machine shop and see if they can replicate the pins out of mild steel, but I'd be surprised if they would do it for less than $6 each without mass-production. I don't know what the pin looks like, so I don't know if it's something that could be made from plain round bar, which is relatively cheap.

I'm probably the biggest proponent of "replace it before it breaks" here, and I do the same thing whenever possible.

 

[DavidM]

I noticed when I purchased the shear pins for our 4000 at Kleen-Rite they did not last nearly as long as the ones from PDQ. KR's lasted just 2-3 weeks and PDQ's last several months usually. I don't know if the cut on the bolt is deeper with KR's or if it has to do with the quality of the Stainless Steel.

It would seem like something you could make if you purchased the bolt and had the ability to cut the groove to a consistent depth.

 

[whitescout]

Windtrax sells the bolt for a little more than $4 each.( M688890). I would rather spend 4 or 6 dollars to replace the bolt, rather than trying to straighten a bent spray bar, or pay for a replacement bar. As much as I don't like engineers, ....... I think they were right by designing this with a shear bolt, rather than a regular bolt.Just my $.02

 

[MEP001]

I think they were right by designing this with a shear bolt, rather than a regular bolt.

Vectors used to use a swing-away on the arm, but for some reason they switched to a shear pin. They still offer it as an option, something I feel should be on any inverted-L auto.

 

[Gabriel]

I was just wondering? Has anyone had problems with break away arms that would make them less desirable than a shear pin? In industrial, slip clutches and equipment break away arms are the standard and I have never in my personal equipment experienced any problem with that technology. In heavy equipment, farm equipment, and in car wash equipment it would seem that it would be a night mare to have shear pins. Break away and slip clutch is used in most all of these applications. I am not criticizing anything, I was just wondering why the old technology that was used in 1930 out board motors is still currently in use in automatic car wash equipment.

 

[galen]

I got tired of the pins breaking so I started using solid bolts. maybe once every two years or so, I take the arm down and straighten it a bit. If someone hits the arm, it sheers it just like the old one. But that has happened only once.

 

[Waxman]

I do the same as Galen. A bolt from the hardware store. Lasts 50x as long as a shear pin in my machine at a fraction of the price.

 

[Gabriel]

On old farm equipment with shear pins, I also have always just substituted a solid bolt. Always got about the same results in real stress situations and probably better results over all. Big savings in convenience and expense. But, I much prefer break away equipment.

 

[bigleo48]

I got tired of the pins breaking so I started using solid bolts. maybe once every two years or so, I take the arm down and straighten it a bit. If someone hits the arm, it sheers it just like the old one. But that has happened only once.

Galen...what kind of machine do you have?

This kinda scares the **** out of me...letting the arm and control mechanism take the full hit every time!

BigLeo

 

[galen]

A Laser. All it will do is bend the arm or shear if someone, I mean some moron runs into it. Mine has been that way for years. Don't do it if you don't feel good about it.

 

[bigleo48]

I spoke to my distributor who's been working on Lasers since thye first came out. He strongly suggests not to replace the shearpin with a solid bolt, but says many do. His concern is damage to the vehicle, more than the arm itself.

He did however give me a tip. He thinks that the life span is shortened if you do not pull the lower arm back completely when tighning the shear pin. If you don't do this, the play in the arm causes a shock to the pin everytime the HP pump kicks in...eventually causing it to break.

BigLeo

 

[PEI]

PDQ's recommends every 3 months on the LW4000, but I have found that we sometimes get bad batches of bolts that will break in just a couple of weeks or even days without actually being hit by a vehicle. Generally, we check the bolt every other week and replace it every 3 months if it makes it that long.

 

[galen]

Bigleo48, I don't understand the advice you were given about "pulling the lower arm completely back". The lower arm and associated block have a hole in them that have to be aligned for the shear pin to slide into. Once the holes are aligned, the arm is where it has to be. If you have a wallered out shear pin hole then that is your problem. Every time the high pressure pump kicks on, the lower arm will apply undo tension on the shear bolt because of "slop" or play.

 

[bigleo48]

Bigleo48, I don't understand the advice you were given about "pulling the lower arm completely back". The lower arm and associated block have a hole in them that have to be aligned for the shear pin to slide into. Once the holes are aligned, the arm is where it has to be. If you have a wallered out shear pin hole then that is your problem. Every time the high pressure pump kicks on, the lower arm will apply undo tension on the shear bolt because of "slop" or play.

Galen, my machine is only a year old and once the pin is in, there is a bit of play. So taking that play out by tighning the ping with the arm pulled back, so when the HP pump kicks, it won't shorten the life of the pin. But I think you get that. So I guess I'm saying that even new, there is enough play to pull back the bottom of the arm almost a couple of inches. I'll see what happens...

BigLeo

 

[lag]

The HP turning on ,and off is what shortens the life of the sheer pin. We replace them every 8-10 weeks , I consider them nothing but preventive maintenance.

I have seen side manifold blocks ,where the pin goes through it wear out ,if you look through the hole it will be oval instead of round. I have also seen weldmonts wear out ,but it happens to the arm most. If you are breaking sheer pins regularly ,you may need to replace the side arm. the other issue that can come up is that the arm will block the front eyes

When you pull back on the arm while installing the sheer pin it will do nothing to make the pin last longer. Watch the arm when HP kicks on , it will kick back,and when it goes off it will move slightly forward. Even though it is solid when you put it in. I can prove it with a very easy test: after installing a new pin,wash a car,go in and push back on the arm ,it will move back. I promise.

We have run solid bolts in the past, but I did not like it because the bolt would bend making it a b***** to separate the arm ,and weldmont. Also I do from time to time have someone hit the arm head on.

Bottom line: replace them regularly, if they keep breaking you may need to replace the arm ,or weldmont.

 

[Gabriel]

Do any of you owners not think that PDQ could improve on this system at very little expense? What about an arm that resets itself? I just do not understand this set up at all.

 

[lag]

Do any of you owners not think that PDQ could improve on this system at very little expense? What about an arm that resets itself? I just do not understand this set up at all.

PDQ wont update the LW4000 ,you have to upgrade to the M5 to get a resetting arm, or you would have to install a Washworld control panel ,Either way it is going to cost pretty penny to have a system that will reset with an impact.