Flex 3401 - Is this normal???

[Xcessiv]

8 months ago, I bought a Flex 3401 to avoid reliability issues with other models like the UDM. I was fully aware of its limitation, like its fragility when applying too much pressure on the extremities.

I think this wasn't enough because 6 months after the purchase and around 5 jobs later, what looked like a tiny plastic ring came off the plate. I ensured that the Allen bolt was tightened properly and everything was perfect. I therefore completed the job flawlessly, without a single sign of abnormal wear.

Today, 2 months after this incident, I decided to open the Flex and see what was going on to be sure that there was nothing wrong and that I'd be ready for the next jobs. The first noticeable thing before removing the plate was a very minor backlash up and down; maybe 1mm. After opening everything, here's the result:




I really don't think this is normal; is it? Should I send it back? Is this typically covered by the warranty?

[vinnier6]

if you bought it here, i would think they would take care of that for you....it doesnt really look normal to me, but then again i am using a pair of udm's and i am not really familuar with the flex....

[wytstang]

I don't think that is normal, it looks like it's eating the plastic away. Can you guess how much pressure you are using? if any?

[ScottB]

it looks like a backing plate failure and what I also incurred. The piece of plastic that came off was part of the plate not a gasket. There is a felt ring and if not lubricated enough it seems to slide up a bit and contacts the backing plate and wears it down. If you got it from AG contact us and sure it will be repaired, if you didnt I believe Powerhouse is their distributor in US.

[gewb]

Hello Xcessiv -

I have owned my Flex only a month and used it an hour so I can't attest to the condition you experienced. However, I have owned many tools for decades and SOME of the conditions you showed are not unusual - but the 8mm bolt rust is ( in my opinion) excessive. Given the environment this tool sees it doesn't surprise me.

The backing plate looks like excessive wear possibly from abrasives. Did you use a light oil on the felt ring? I will comment: the type of "plastic" used in the bp is able to take relatively high heat before deforming, as in greater than 300 degrees F (I have over 7 years year of engineered plastics molding experience). I think it is just worn out from the abrasives.

Given your experience and that of others, I have taken my 3401 apart and performed the following preventative maintenance:

> Lubed the internal gear (number 294.357) with the lube pooled in the "well"
> Added three drops of full synthetic oil (30W) into the assembly that attaches to the bp mounting bolt (numbers 322.105, 259.148, 104.949)
> Covered the interal steel parts (counterweight, etc.) with a thin coating of synthetic grease (numbers 322.083, 322.156)
> Added a light coat of synthetic grease onto/around the plastic gears (numbers 328.200, 322.121)
> Added 12 drops of light machine oil into the felt ring (number 331.066)
> Coated the 8mm bolt and washer with a light film of synthetic grease (numbers 255.964, 278.254)
> Added a light coat of synthetic grease into the bolt hole (number 322.105)
> Added an internal star washer between the washer and bolt head (numbers 255.964, 278.254)

Running the Flex "dry" (no pad, no load) at lower speeds after doing the above made a noticable change in the sounds it makes - quieter and smoother.

The sythetic grease I used is Permatex Ultra Disc Brake Lube (in the green Counterman's Choice 0.5g package).

http://www.permatex.com/products/Aut...per_Lube_1.htm

http://www.permatex.com/products/Aut...Brake_Lube.htm

Next time I go to the hardware store I'll look for a stainless steel bolt. I'll also order one or two replacement felt rings as it looks to be a part that should wear (by design) and be replaced (Flex should include the felt ring with the replacement bp).

Regards,
GEWB

[Xcessiv]

Ok, so I got the replacement parts (backing plate and ring gear).

Looking at the ring gear, what could have caused this damage?


My warranty is ending soon. If it's a bearing, I'll try to get it replaced now.

[Harrison]

Seeing and reading all of these back plate issues with the Flex is kinda making me lean towards the Cyclo..... I read this below on another site and was wondering if it's a different BP or the same one. A new style or same but different size. Going to buy one today and I am so up in the air between the two. I don't want to spend money on a machince that I have to worry about it breaking. Here is what I found....


The Velcro backing plate is a specially made, geared backing plate that creates the forced rotation. The Flex XC 3401 VRG originally came with a 6" backing plate but it had problem with seperation between the velcro and the backing plate. They are offering a replacement backing plate for anyone who has the original backing plate (contact your place of purchase for more information). The new backing plate is much better then the original, not only is it smaller (5.5" instead of 6") they also added a foam cushion in between the velcro and backing plate. This foam cushion allows for flexablity and a bit more distance between the machine and pad. The smaller backing plate also allows you to use 6" pads.

[Dwayne]

Looking at the ring gear, what could have caused this damage?

Were you tilting the machine at all while applying pressure?

[Xcessiv]

Were you tilting the machine at all while applying pressure?

Could have been the case under some occasions when I had no other option but I really minimized this.

[YankeeFan]

Seeing and reading all of these back plate issues with the Flex is kinda making me lean towards the Cyclo.....

Actually I think the Makita 6040 is very close to the Flex. From what I hear it's designed differently as the backing plate is not a part of the gear system as the Flex has, which is causing all the problems. That also will help if you use the Edge system. Can anyone with a Makita chime in?

Howard