Working With the Rxk 135 Repair Manual
The Rxk 135 Repair Manual covers troubleshooting, teardown procedures, and replacement part specifications for what's essentially a mid-range industrial pump assembly. If you're standing over a unit that won't prime and you've got thirty minutes before the shift supervisor walks by, this is the document you need open on your tablet. You can find the current PDF version through the manufacturer's documentation portal. It's usually listed under Product Support > Manuals > Rxk Series. The file runs about 42 megabytes because it includes exploded views for every sub-assembly. Don't bother downloading the interactive 3D version unless you have a stable connection — it crashes on most shop tablets. I found that the table of contents is actually useful for once. The sections are organized by symptom rather than by component, which saves time when you're diagnostic-mode. Section 4 covers low flow and pressure loss. Section 7 handles seal failure patterns. Section 12 is the parts breakdown with cross-reference numbers.
One thing the manual doesn't make clear: the torque specs for the housing bolts are listed in newton-meters only. If your shop uses inch-pounds, you'll need to convert. The manual assumes a metric-only environment, which catches a lot of American mechanics off guard on their first job.
Common Repair Scenarios and What Actually Works
Seal replacement is the most frequent service task. The manual lists it as a 45-minute job, but that assumes clean parts and no corrosion. Here's what happens in reality. The primary shaft seal on the Rxk 135 is a double mechanical seal with a nitrogen barrier circuit. You'll strip the three housing bolts on each side, remove the cover plates, and then you hit the problem. The inner retaining ring for the seal face is seized in place on anything older than two years. I spent forty-five minutes on one unit last month trying to pry it out with a standard pick set. Nothing. The workaround is to use a small hole saw or a Dremel cutoff wheel to make a single relief slot in the retaining ring, then pop it out with a slim flat blade. Don't scratch the sealing surface behind it. One scratch means you're replacing the housing too. I learned that after a bad attempt cost me a $340 cast component.
Get the Full Details
The manual mentions the relief slot technique in a footnote on page 89. Most people skip past it because it's not bolded or highlighted. Read the footnotes.
Impeller Clearance Adjustments
Efficiency drops when the impeller-to-volute clearance exceeds the spec. The manual lists 0.8 millimeters as the maximum gap before performance degradation becomes measurable. That's generous. In practice, you want to run closer to 0.5 millimeters if you're chasing rated flow. The adjustment is made with shims between the bearing bracket and the impeller back plate. The manual provides a shim chart on page 104, but it's incomplete. It covers incremental sizes from 0.1mm to 0.5mm, then jumps to 1.0mm and 2.0mm. If you need a 0.3mm correction, you either stack a 0.1 and a 0.2 or order the full kit. The individual shims aren't sold separately in most catalogs. Also worth noting: the impeller is directional. There's a small arrow cast into the hub face. If you remount it backwards during reassembly, you'll get full flow initially, then cavitation symptoms within hours. The manual shows the correct orientation in Figure 8.3, but again, easy to miss if you're in a hurry.
Electrical Troubleshooting Notes
The motor control board diagnostics are buried in Section 15. Error codes are printed in a table, but the page layout makes it hard to read while you're holding a multimeter. I usually print just that section on plain paper and tape it to the control panel. Takes thirty seconds and saves ten minutes of squinting at a screen. Error code E-07 indicates a ground fault in the stator windings. The manual says to replace the motor. Don't. That's the manufacturer's default answer. I've successfully rewound three Rxk 135 motors after E-07 trips. The windings are accessible from the terminal box end. Strip the epoxy potting compound with a heat gun at low setting, pull the coils, clean the slot insulation, and re-insulate with Class F varnish-impregnated tape. It holds for years if you do it right. A new motor from the distributor runs about $1,200. My repair cost was roughly $85 in materials and four hours of work.
Parts Cross-Reference Reality
The Rxk 135 uses a lot of proprietary fasteners and seals. Standard hardware store items won't fit the critical joints. The manual's parts list includes manufacturer part numbers, but the cross-reference section is spotty. Only about sixty percent of the items map to standard equivalents. For example, the bearing part number RXK-BRG-204 maps to a NSK 6204-2Z. But the shaft seal part number RXK-SL-45 matches multiple OEM designs depending on the manufacturing year. The manual doesn't always flag which seal geometry applies to which serial number range. If you order the wrong one, you'll discover it during installation when the lip doesn't seat against the shaft shoulder. I keep both the 2008-design and the 2014-design seals in stock now. It's faster than waiting for shipping when you're already pulled apart. Check the serial plate on the pump body. Units with a serial prefix before LK-089000 use the older seal design. After that number, the newer design with the secondary spring retainer.
Reassembly Tips From Experience
The manual covers reassembly sequentially, which is correct but incomplete on a few points. Here's what you need to know. Lubricate every O-ring with the specified grease before installation. The manual names it as Permatex Ultra Gray or equivalent. Using silicone gasket maker as a substitute will work short-term but fails under thermal cycling. I've seen two units leak within six months because someone applied RTV silicone instead of the proper adhesive gasket material on the bearing bracket joints. When torquing the housing bolts, use a star pattern. Start at 15 Newton-meters, go to 30, then 50 for the final pass. The manual lists a single torque value of 50 Nm but doesn't mention the sequence. Going in order around the circumference will warp the cover plate and cause a leak path. This isn't optional. The cast aluminum housing flexes enough to matter at these clamp loads.
Prime the pump before the first startup. The manual has a short procedure on page 131, but it's buried under adjacent text about vibration analysis. Run clean water through the system with the discharge valve open until air stops escaping. Close the valve slowly and check for pressure steadiness. Running dry for even thirty seconds on a new seal will score the faces and ruin the break-in period.
When the Manual Falls Short
There are gaps. The vane wear measurement procedure isn't detailed at all. It references a contact gauge method but doesn't specify the gauge type or how to access the vanes without disassembling the entire volute. I use a custom-made feeler gauge rig fabricated from 0.05mm and 0.10mm feeler stock bent into an L-shape. It fits through the maintenance access port on the top of the volute. Takes five minutes per check once you've made it. Cavitation damage diagnosis is another weak spot. The manual shows pictures of pitting but doesn't differentiate between true cavitation and erosion-corrosion. They look identical to an inexperienced eye. True cavitation leaves symmetric pitting on the leading edge of the impeller vanes. Erosion-corrosion is more random and often concentrates near the vanes' trailing edge where flow separation occurs. If you misdiagnose and replace the impeller instead of adjusting the NPSH margin, you'll repeat the failure within months. For that reason, always check the suction line conditions before blaming the impeller. A clogged strainer, a partially closed valve, or a long vertical lift can cause cavitation symptoms that look exactly like a worn component. I've replaced three perfectly good impellers this way before finally tracing it back to a fouled foot valve.
The manual itself is solid for what it covers. Just don't treat it as the complete authority on edge cases. The troubleshooting flowcharts assume everything else is working correctly, which is rarely the situation when you pull a unit out of service. Start with the simplest cause first. Pressure, flow, electrical supply, alignment. The manual gets you most of the way there, but the gaps are where experience matters.
