Official: Masterflex Repair Thread

[tkeracer619]

Now that there are a bunch of reefers using Cole-Parmer Masterflex Peristaltic Pumps I though it would be wise to start a thread devoted to keeping track of any repairs we make to the units. They are pretty pricey and there isn't much info out there regarding repair so if you are a hero and take one of these apart please document it for the rest of us.

[tkeracer619]

My 77301-21 brush-less modular pump drive finally crapped out after 9 years of running 24/7. The controller displayed a stall error and after checking it out the unit would not manually spin. This series of posts covers the replacement of the bearings for this particular pump drive.

This is the first one of these I have torn apart and I am not sure how this translates into other units but I have a feeling most of the brushless units will be similar. Expect around 1.5-2 hours to complete the job.

I recommend using high quality NACHI or NTN bearings.

To replace the bearings you will need the following.
- Moody Tools, .048" 4 Flute Spline Blade Driver, Part # 49-8047
- Front Bearing, 608 Double Sealed
- Rear Bearing, R6 Double Sealed
- Slotted Screwdriver
- #2 Phillips Screwdriver
- Eyeglass Phillips
- Snap Ring Pliers
- Deep Socket Set
- Bearing puller
- Rubber Hammer
- Rubber Gloves
- Paper Towels
- High Quality Synthetic Grease
- Fresh Razor knife
- Torx Driver

Please take your time doing this, replacement parts may not be easy to find! Go ahead and wipe off any old grease as you disassemble.

Read all steps and familiarize yourself with the procedure before starting. Take extra care when dealing with the encoder!!!

1. Start by removing these 4 screws and remove the front cover, this will expose the gearing. Remove the gasket and put away for safe keeping.

https://c2.staticflickr.com/6/5794/30451763583_9002d53426_c.jpg

2. Remove the reduction gear, clean, and set aside in a safe place for later. There is a shaft, a gear, a thrust washer, a bushing, and two shaft keys.

https://c2.staticflickr.com/6/5800/30438144924_4c18113f35_c.jpg

3. The giblets from the previous step. Note the orientation of parts as you take them off. They need to go back in the same orientation when putting the drive back together.

https://c2.staticflickr.com/6/5680/30438143384_e0ca0c5789_c.jpg

4. At this point you will be left with just the motor.

https://c2.staticflickr.com/6/5469/31115720332_6cf933da08_c.jpg

5. Remove the wire restraint (nut and cord grip) and the two screws that hold the end bell on. There is an oring that keeps the end bell sealed so expect some resistance pulling the end bell off. Pull it directly off.

https://c2.staticflickr.com/6/5599/31223480486_459310dd57_c.jpg

6. Clip the two zip ties that secure the wiring to the standoffs.

https://c2.staticflickr.com/6/5796/31115632652_0f1c324fd1_c.jpg

7. Remove the chassis grounds and the two other philips head screws from the back plate. Remove the plate to expose the encoder. Thread the screws back in for safe keeping and put the back plate off to the side.

https://c2.staticflickr.com/6/5510/31115692632_c41632d438_c.jpg

https://c2.staticflickr.com/6/5658/31144892351_6bfc2048fa_c.jpg

8. Now that the encoder is exposed go ahead and mark where the nuts and standoffs are.

https://c2.staticflickr.com/6/5616/30891747360_0a4a4f27f6_c.jpg

[tkeracer619]

9. The encoder is very fragile, do not try to force anything. Remove the plug from the encoder. Before moving to the next step use a sharp razor knife to mark the location of both the encoder body to the motor case and the encoder wheel to the shaft (green circles). DO NOT TAKE OFF THE ENCODER COVER YET!!!!

https://c2.staticflickr.com/6/5662/30451660383_2a3483dea6_c.jpg

This image was taken during assembly to show the markings, the one taken during disassembly didn't show one of the markings.
https://c2.staticflickr.com/6/5722/31144889111_88c662a5c5_c.jpg

10. Please be careful during this step. The encoder is easily damaged. Peel back the label to expose the two screws that hold the cover on (green arrows). Remove them with a small phillips screwdriver. Remove the two torx screws (Red Arrows) DO NOT PULL OFF THE ENCODER!!

The yellow circle is a clip that holds that side of the encoder housing together. I broke mine off by accident, no worries if that happens. You will need to split the two housings apart by pulling up on the locking tab (green circle) while using a razor knife to keep the bottom half of the encoder housing in place. Lifting the encoder housing off of the motor will damage the encoder wheel.

https://c2.staticflickr.com/6/5752/30891744160_3794b19fb1_c.jpg

11. Use the 4 flute Moody Tools driver to loosen the set screw on the encoder coller (Red Circle). Slowly lift the encoder by the coller. Remove the bottom half of the housing. Re-assemble the encoder inside it's housing using the small phillips screws and put the encoder in a safe place.

https://c2.staticflickr.com/6/5722/31144889111_88c662a5c5_c.jpg

12. Use a pair of plyers to compress and remove the wire restraint off the back of the motor.

https://c2.staticflickr.com/6/5713/31144886081_51932d0ae0_c.jpg

https://c2.staticflickr.com/6/5473/31115717892_112118aac7_c.jpg

13. Remove the two nuts and two standoffs from the back of the motor.

https://c2.staticflickr.com/6/5807/31115716652_cabc8eceb3_c.jpg

14. Remove the C Clip from the shaft and put to the side.

https://c2.staticflickr.com/6/5679/30891738380_3ea0b08143_c.jpg

15. On the exposed shaft inside the gearbox side of the motor use a small block of wood and rubber hammer to tap out the internals and motor back plate.

Once the plate is loose remove it and the shaft as a unit from the rest of the motor. Take care not to tug on any wires.

16. Remove the large C Clip from the motor back plate and gently tap the shaft from the back plate.

https://c2.staticflickr.com/6/5484/31144882141_c0d8c37252_c.jpg

17. Now that you have the shaft and bearings out of the motor use a bearing puller to remove the old bearings.

https://c2.staticflickr.com/6/5675/31115710392_6886b7386b_c.jpg

[tkeracer619]

Take note the orientation of the spring washer (at front bearing) and thrust washer (at rear bearing)! Make sure these make it back in.

https://c2.staticflickr.com/6/5736/30438148404_63000b6e99_c.jpg

https://c2.staticflickr.com/6/5486/31115712072_e7816a6687_c.jpg

18. In my case the rear bearing failed. Here are the old bearings.

https://c2.staticflickr.com/6/5773/30451770713_9c02ca770e_c.jpg

19. Press on the new bearings. I used a washer over the new bearing and tapped the new bearings in place by using a deep socket. Make sure the washer only contacts the inner race, you don't want to damage the shield or bearings.

https://c2.staticflickr.com/6/5501/31259347555_9ba0b665a3_c.jpg

https://c2.staticflickr.com/6/5625/31115707812_a010da374e_c.jpg

20. Now that you have the new bearings fully seated make sure the spring washer and thrust washer are in the proper place. Re assemble the unit exactly how you took it apart. Please take care when re-installing the encoder!!!

21. When assembling the gearbox make sure to give everything a good coating of grease and then put a blob of grease on the bottom at one side of the reduction gear.

https://c2.staticflickr.com/6/5786/31259363585_4f913bafed_c.jpg

22. Hopefully if everything went well and you now have a functioning drive again. With care these drives can last a very long time with continuous operation.

[JamesHolt]

Why did you disassemble the encoder before removing it, from here it looks like just the two screws and the set screw in the shaft...

[tkeracer619]

You may be able to just pull it off as you can access the set screw without taking the cover off. The simple answer is you may not be able to get another and I didn't want to risk damaging the encoder wheel by pulling on it with the case. A local reefer is working on getting a new one because it was damaged while removing it with the cover intact. I'm sure he will post his progress here. It comes apart easily so I chose not to risk it.

[NeverlosT]

Pretty cool! Good writeup.

I may replace the caps on my motor transformer to see if I can reduce the humming noise some. If I do, and if it is successful, I will post instruction here.

[tkeracer619]

Great! Thanks!

[Knishfish]

I bought this head second hand a couple of years ago. All of a sudden, it's not holding it's prime. I took the head apart. No big deal. Removed 6 screws. Cleaned the 4 wheels and reassembled. Tubing has been replaced and is same #16 tubing I have been using. Still not holding the prime. Not sure how to fix the head so any suggestions are welcome.

[tkeracer619]

My first guess is the bearings that support the rotor have worn out and have gotten sloppy.

Take the head off the pump, unlatch it so there is no pressure on the rotor, and wiggle the drive tab on the back. Is it loose? If yes you'll want to swap the bearings.

[Knishfish]

Taking the head apart, cleaning all the parts and putting it back together again did the trick

[foxt]

Great idea for a thread!

I have a CP 7525-30 0-100 RPM digi staltic pump that had a loud hum. Given the age of the unit, I concluded that the hum was in part coming from the transformer coil. Over time, the layers of iron material which were glued together during manufacturing work their way loose, and the vibration between the plates results in the 60hz hum you hear.

Replacement was easy: desolder the existing transformer coil, and replace with a new one. The part number on my unit was Triad FP16-750, and is still in production - $12 delivered!

After it arrived, about 30 mins later with some solder wicking and some grumbling about needing smaller fingers, I had the swap completed. Powered the unit up, and although there is still a slight hum, it was dramatically quieter.

I ran the pump through it's paces, and was happy with the result. At low RPM (less than 40), I can hear the slight hum, but the pump is falrly quiet. At higher RPM, the noise of the pump head itself masks the hum (that wasn't the case before the swap).

A couple of days later, I was fiddling with the reverse-off-forward switch, and inadvertently switched from forward through off, to reverse while the pump was running. Oops! This caused the fuse (this unit has an external fuse mounted to the rear) to blow. I replaced the fuse, only to discover that the unit is now stuck in a high-speed mode: RPMs only vary from 120 to 130 when dialing in the speed.

Resets, attempts to recalibrate, and general poking around in the circuitry have yielded no change. I guess I fried something, but I am not sure what. CP has been responsive, but given the age of the pump, they're not able to offer any assistance.

Being an EE, I feel as though I should be able to figure this out. I ran through the limited onboard diagnostics, and that all checks out. Because of that, I think the microprocessor side of things is still ok. Since the fuse blew, that suggests a power surge, which suggests a semiconductor somewhere probably took a hit.

Does anyone have any experience with repairing the variable speed control on one of these older digi-staltic units?

[Bpb]

Well this is all way over my head. The day my masterflex dies I'll have a tough decision to make. Buy a new one or go back to 2 part


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[yellojello]

Does anyone know what size and which brand you recommend for the head bearings?

[Haksar]

Good write up as always .
I am using a 7523-40 and this would help
if I need over haul .
Many thanks.

[yellojello]

Actually looked on my head bearing, and it shows "R8L8". So I guess it is R8 size, but no idea what L8 is. I'll assume it should be double sealed, so R8-2RS is what I should find. I think the previous owner had some tubing splits, never washed off the salt water, and rusted the bearings.

[Frank@wall]

This isn't a repair but more so a programming question within the masterflex pump. I have the 7523-60 and I thought it can dispense 0.6ml/min-3400ml/min but I cannot get it below 30ml. What am I doing wrong?

Sent from my SM-N950U using Tapatalk

[Knishfish]

I found they had amazing customer service.

[tkeracer619]

This isn't a repair but more so a programming question within the masterflex pump. I have the 7523-60 and I thought it can dispense 0.6ml/min-3400ml/min but I cannot get it below 30ml. What am I doing wrong?

Sent from my SM-N950U using Tapatalk

Flow depends on your tubing set. To go lower you probably need to change to a lower tubing set.

[tkeracer619]

Actually looked on my head bearing, and it shows "R8L8". So I guess it is R8 size, but no idea what L8 is. I'll assume it should be double sealed, so R8-2RS is what I should find. I think the previous owner had some tubing splits, never washed off the salt water, and rusted the bearings.

That sucks. I list the bearings my motor had up top in the thread, but depending on your model they may be different. You want a high quality bearing double sealed.

[gdemos]

Please Refer to #2726 Post in Official Masterflex CaRx setup thread:
Appreciate any help! -Greg

I identified the P?0 code had to do with local/remote control setting and fixed that

Now i find that the belt wheel has some play on the shaft (moving belt closer/further to the head)

The belt wheel tends to move further from the head therefore the male end of head is not contacting the belt wheel

Looks like if there were a bushing in the belt wheel shaft it would hold the wheel to the head , but there is no such bushing.

Please look at the pics. Is the male end of this head worn down? Pica show amount of play in belt wheel.

[awais98]

Thanks to tkeracer
I was able to change the 2 bearings successfully. And I’m not a mechanical person!!
Without your help with the names of the tools it would have been impossible!
Appreciate your help a lot.
I can’t stress enough, how important it is to follow each step carefully, and pay in special attention to the decoder. It IS fragile.
Some of the pics

https://uploads.tapatalk-cdn.com/20180513/6b42cc3bbbc69a2fa7f6493e5c99d66d.jpghttps://uploads.tapatalk-cdn.com/20180513/1326d3bb6897c5090d432ae1b99c8c09.jpghttps://uploads.tapatalk-cdn.com/20180513/994fcad3f4e144efcd49c687d28ca1b1.jpghttps://uploads.tapatalk-cdn.com/20180513/6d0f8700f19b9fa19dd117d8505a863a.jpghttps://uploads.tapatalk-cdn.com/20180513/df95d6bf23b965fe7a0970b0ffefc07d.jpghttps://uploads.tapatalk-cdn.com/20180513/b25be90ecd1724105903ed270fec23c9.jpg


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[Wills612]

Bearings in my easy load head were not sealed and everntually developed a squeke. The two bearings in the head are 1/2x1-1/8x5/16.
Part number: r8-2rs

[tkeracer619]

Thanks to tkeracer
I was able to change the 2 bearings successfully. And I’m not a mechanical person!!
Without your help with the names of the tools it would have been impossible!
Appreciate your help a lot.
I can’t stress enough, how important it is to follow each step carefully, and pay in special attention to the decoder. It IS fragile.
Some of the pics

https://uploads.tapatalk-cdn.com/20180513/6b42cc3bbbc69a2fa7f6493e5c99d66d.jpghttps://uploads.tapatalk-cdn.com/20180513/1326d3bb6897c5090d432ae1b99c8c09.jpghttps://uploads.tapatalk-cdn.com/20180513/994fcad3f4e144efcd49c687d28ca1b1.jpghttps://uploads.tapatalk-cdn.com/20180513/6d0f8700f19b9fa19dd117d8505a863a.jpghttps://uploads.tapatalk-cdn.com/20180513/df95d6bf23b965fe7a0970b0ffefc07d.jpghttps://uploads.tapatalk-cdn.com/20180513/b25be90ecd1724105903ed270fec23c9.jpg


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Awesome! Glad this was helpful!

[tkeracer619]

Bearings in my easy load head were not sealed and everntually developed a squeke. The two bearings in the head are 1/2x1-1/8x5/16.
Part number: r8-2rs

Replace with a sealed bearing. I recommend nachi or ntn. Most suppy shops will have these in stock. The smoother the better!

[fishyguy7]

Heads up for people that attempt to repair these. The encoder IS NOT AVAILABLE ANYWHERE!!! I have contacted Cole parmer as well as the encoder manufacturer Renco. So be very careful with them !

[gdemos]

Official: Masterflex Calcium Reactor Setup Thread
https://r.tapatalk.com/shareLink?share_fid=1489&share_tid=2368618&share_pid=25506434&url=http%3A%2F%2Fwww%2Ereefcentral%2Ecom%2Fforums%2Fshowthread%2Ephp%3Fp%3D25506434&share_type=t


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[fishyguy7]

Official: Masterflex Calcium Reactor Setup Thread
https://r.tapatalk.com/shareLink?share_fid=1489&share_tid=2368618&share_pid=25506434&url=http%3A%2F%2Fwww%2Ereefcentral%2Ecom%2Fforums%2Fshowthread%2Ephp%3Fp%3D25506434&share_type=t


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That’s interesting

[tkeracer619]

That’s interesting

Have you ever found a replacement?

[fishyguy7]

Have you ever found a replacement?

No I contacted both cole parmer and the original manufacturer of the encoder Renco and was told NO replacements are available anywhere

[tkeracer619]

No I contacted both cole parmer and the original manufacturer of the encoder Renco and was told NO replacements are available anywhere

One of my brushless controllers kicked the bucket a few weeks back. Going to try to repair it but if I can't I may have a motor available :(

It was the setup featured in this thread... My first Masterflex. Ran nonstop for 10 years but had it stuffed in a small cabinet. I think heat took it's toll on the controller.

[yellojello]

Does anyone know if this is the same fixed for a brushed motor? 7557-02.

Getting Error #3: Instantaneous Over-Current
Description: Motor is drawing too much current for a short duration
of time.
Error Condition(s): The motor current is above 4.0 A peak.
Actions: Drive will stop immediately. Verify that pump head is not
binding and that the load is not above recommended
maximum load. If error persists consult factory.

Perhaps I'll just replace brushes first, but might be rear bearing? Opened front cover and saw little black dust settled. It will still run without the head on.

[yellojello]

Some photos of 7557-02 Motor. One of the bearings was seized and replacement was easy... however... I am now getting ERR 1 which seems to be encoder error. Not sure how to fix yet, but the encoder doesn't seem that delicate on this model.

https://imgur.com/WCsMAWa.jpg

https://imgur.com/qRbqdsq.jpg

https://imgur.com/ysvLpRu.jpg

https://imgur.com/H9JnXaD.jpg

https://imgur.com/Fksi1iq.jpg

https://imgur.com/k3Kfgnx.jpg

https://imgur.com/GYXSggv.jpg

https://imgur.com/41l2wDy.jpg

https://imgur.com/cZZo7i4.jpg

https://imgur.com/sLhBbfQ.jpg

[yellojello]

https://imgur.com/tjMopLw.jpg

https://imgur.com/B9G1vIQ.jpg

https://imgur.com/y1HBzBy.jpg

https://imgur.com/naFwNay.jpg

https://imgur.com/lcH2xD7.jpg

https://imgur.com/7sXsOAF.jpg

[yellojello]

WOW! It wasn't an encoder issue at all. TLDR: One of the brushes wasn't making contact with the motor, trouble going through the hole.

After letting it sit for a while and let my frustration go away and resist to send it in for "repair" and $$$, I tried to troubleshoot again. So I turned it on, and began turning the motor by hand right before pushing the Play/Start key, and while keep turning it by hand, after I pushed Play/Start key the RPM would actually readout the number for a second or two before going to Error 1. That gave me hope that it wasn't an encoder issue at all. So I opened the motor back up and troubleshoot the motor itself. I looked this video up real quick "How to troubleshoot brushed DC motor" https://www.youtube.com/watch?v=sWEsPw733h8

I put my multimeter on the positive and negative leads and got nothing. Tried the 9v battery and nothing. I took a closer look and ended up being one of the brushes wasn't fitting through the hole properly and no contact to the motor. After I verified both brushes making contact again, the multimeter was reading some resistance and the 9v battery made the motor run. All is good, no encoder issue, and save me some $$$.

[tkeracer619]

Excellent, thanks for sharing!