12v pumps

12V Soft Wash Pump Leaking? Snug the Head Screws Before You Replace Anything

Sep 29, 2026 Tim Cray 4 min read

Key takeaways

A drip at the head seam is usually loose screws, not a failed seal. The polypropylene head and Viton seal relax under clamp load while the pump sits on shelves, and vibration against a bleach mix finishes the job.
Even brand-new pumps need it. The out-of-the-box Remco 5.3 in the video turned on every screw; that's normal, not defective.
T20 Torx, hand screwdriver, never an impact. Snug each screw with light hand pressure until it stops, usually a sixteenth to an eighth of a turn, then do the other side.
Don't go past snug. An over-torqued screw strips or cracks the polypropylene boss and then you really do need a new head.
Do it on the bench before the first run. Every pump on our builds gets snugged before it's plumbed; if it still leaks afterward, look at the diaphragm, seal, fittings and quick-connects.

In this guide

12V Soft Wash Pump Leaking? Snug the Head Screws Before You Replace Anything - Expert Power Wash

A 12V soft wash pump with a drip coming from the seam where the pump head meets the motor looks like a failed seal. Most of the time it is not. The screws that clamp the head down have relaxed a little, and the fix is a small screwdriver and about two minutes. In the video we have two pumps on the bench: a customer's Remco 7 GPM dual control that came in with problems, and a Remco 5.3 straight out of the box that had never been hooked up. Both of them needed it.

Why the head screws loosen

The pump head on a Remco is polypropylene and the seal between the head and the motor housing is a rubber (Viton) seal. Both of those materials flex. The pump gets assembled at the factory, sits on a shelf at Remco, sits on a shelf at a distributor, sits in a box on a truck, and the whole time the plastic and rubber are slowly relaxing under the clamp load. By the time you put it into service, the screws are not as tight as they were the day it was assembled. Add the vibration of a pump running against a bleach mix all day and you have a weep.

That is why the brand-new 5.3 in the video turned. It was not defective. It was normal.

What you need

The head screws take a T20 Torx bit. Use a hand screwdriver, not an impact driver. You are not trying to crush anything; you are taking up the slack that the plastic and rubber gave back. An impact on a polypropylene head is how you end up buying a new pump head.

How to do it

Go around the head one screw at a time and give each one a gentle snug. Watch the screwdriver as you turn it: on the pumps in the video every screw moved somewhere between a sixteenth and an eighth of a turn before it seated. That is the whole adjustment. When the screw stops with light hand pressure, stop. Then flip the pump over and do the screws on the other side the same way.

Remco publishes a torque spec for these, and if you have a small torque driver you can chase it. In practice, light hand pressure on a T20 driver until the screw stops is what we do, and it is what has worked on hundreds of pumps. The failure mode to avoid is going past snug, because an over-torqued screw in polypropylene strips or cracks the boss and now you really do have a bad head.

Do it before the first run, not after the first leak

Every pump that goes onto one of our builds gets this done on the bench before it is plumbed, whether it is a bare pump or the pump on one of our plate-mounted FloJet assemblies. If you are buying a pump and installing it yourself, do the same thing. It is much easier with the pump in your hand than with it bolted into a skid behind a mixer.

If you already have a pump in service and it has never been checked, check it at the next rinse. It is a two-minute job on the rig.

If it still leaks after snugging

Then it is time to look harder. A pump that has been run dry, run hot, or left full of bleach overnight for a season can have a genuinely damaged diaphragm or seal, and no amount of screw tightening fixes that. The head assembly on the 7 GPM FatBoy is a bolt-on replacement. Also check the obvious: a leak at a fitting or a cracked quick-connect can run down the body and look like a head leak. Remco's quick-connect hose barbs are cheap and worth swapping on suspicion.

The habit that matters more than any of this is rinsing the pump after every job, not once at the end of the day. We go into why in 12V Soft Wash Pump Setup: Why Most of Them Die Early.

Parts mentioned

Remco 5.3 GPM 12V soft wash pump
Remco 7 GPM 12V soft wash pump
Remco 5500 / FatBoy series screw kit — all ten head screws, if any are stripped or missing
Remco FatBoy 7 GPM pump head assembly
Remco pressure switch, 5500 series and 7 GPM pressure switch and relay
All 12V soft wash pumps and parts

Frequently asked questions

Why is my Remco 12V soft wash pump leaking where the head meets the motor?

Most of the time it isn't a failed seal. The pump head is polypropylene and the seal is Viton rubber, and both relax under clamp load while the pump sits on shelves and in boxes before you ever run it. Add the vibration of running against a bleach mix all day and the head screws end up a little loose, which shows up as a weep at the seam.

What size bit do Remco pump head screws take?

The head screws take a T20 Torx bit. Use a hand screwdriver, not an impact driver. You're only taking up the slack the plastic and rubber gave back, and an impact on a polypropylene head is how you end up buying a new pump head.

How tight should the head screws be on a Remco soft wash pump?

Go around one screw at a time with light hand pressure on a T20 driver and stop when the screw stops. On the pumps in the video each screw moved between a sixteenth and an eighth of a turn before it seated. Remco publishes a torque spec if you have a small torque driver, but light hand pressure until it stops is what we do and it has worked on hundreds of pumps. Over-torquing strips or cracks the boss.

Do I need to tighten the head screws on a brand-new soft wash pump?

Yes. The brand-new Remco 5.3 in the video had never been hooked up and every screw still turned. That's normal, not a defect. Every pump that goes onto one of our builds gets snugged on the bench before it's plumbed, and it's much easier with the pump in your hand than bolted into a skid behind a mixer.

My soft wash pump still leaks after tightening the head screws. What now?

Then look harder. A pump that has been run dry, run hot, or left full of bleach overnight for a season can have a genuinely damaged diaphragm or seal, and no amount of tightening fixes that; the head assembly on the 7 GPM FatBoy is a bolt-on replacement. Also check the obvious: a leak at a fitting or a cracked quick-connect can run down the body and look like a head leak.

What is the best way to keep a 12V soft wash pump from leaking?

Snug the head screws before the first run, and if a pump is already in service and has never been checked, do it at the next rinse; it's a two-minute job on the rig. The habit that matters more than any of this is rinsing the pump after every job, not once at the end of the day.

Written by

Tim Cray

Owner, Expert Power Wash

Tim and Kristina ran their own pressure washing company for more than ten years on trailers, box trucks, flatbeds, vans and skids before Expert Power Wash started building equipment for other contractors. Today EPW has 300-plus builds working in the field and services pressure washing rigs in the Oregon City shop every day.