Our debris body developed a weep with no visible rust. How?

Erosion, not corrosion. Debris enters at high velocity through a fixed inlet and sandblasts the same patch of shell every operating hour, thinning it from the inside. The outside stays painted and sound looking until a pinhole appears. We repair the area and can add wear plate protection where the shell has thinned.

The machine has lost suction and the blower checks out. What next?

Look at the tailgate sealing ring. The body holds vacuum against a machined ring face, and debris caught during closing scores it while residue corrodes it. We assess the ring with the gate raised, check hinge bore ovality since a crooked gate scores a ring, then restore the face and reset locking bar geometry.

There is a knock at the start of every boom swing. Bearing or mount?

In our experience the mount, far more often than the bearing. Each swing reverses the moment on the pedestal welded to the body or subframe, so cracks form at that weld line. We dye penetrant the full accessible weld line and coordinate with the equipment service provider if the bearing must come off for access.

Will your technicians go inside the debris tank to weld?

No, under no circumstances and regardless of how recently it was cleaned. A debris body is a confined space with a biological and chemical hazard history, and a collision shop is the wrong organization to enter one. We repair from the outside using borescopes and thickness gauges, or the district arranges a specialist for interior work.

What condition does the unit have to arrive in?

Dumped, flushed and accompanied by a cleaning certificate from the district or its contractor, in writing, before we open anything. A $45 flat hazmat and disposal charge applies where contaminated residue or chemicals are involved in the work itself. On a properly cleaned unit that generally does not arise.

We only have one combination unit. How do you handle that?

We order every part before intake and do not start until the parts are physically here, so the truck is never sitting in our building waiting for a delivery. We also say plainly at estimate stage how many days the unit will be down, because a district with no cleaning capability builds a backlog fast.

Buses and Fleet

Sewer Vacuum Truck Body and Debris Tank Repair

Written by Structural Repair Lead, Structural and Frame Lead, OCRV Center. Reviewed by Fleet Account Manager

In shortA debris body is a pressure and vacuum vessel full of abrasive slurry, and it wears at the tailgate ring and the shell wall. The boom rotation mount is the other structure that matters.

What does sewer vacuum truck body repair involve?

Sewer vacuum truck repair covers the debris body shell and tailgate sealing ring, the locking bar and hinge structure, boom rotation bearing mounting, water tank cradles and hose reel frames. Utility districts near Rancho Santa Margarita send these units to our Yorba Linda facility dumped, flushed and certified clean before we open anything.

Shell wear concentrates where the inlet stream lands
The tailgate ring seal face is a machined surface, not a flange
We do not enter a debris body under any circumstances
Units arrive cleaned and certified by the operator

Units serviced: Vactor 2100i, Aquatech B10, Vac-Con, Sewer Equipment jettersOn Freightliner 114SD, Peterbilt 348 and International HV chassis
Structural rate: $210 per hourShell, ring and mount welding in the body department
Typical length: 30 to 38 feetGVWR 54,000 to 66,000 lb on a tandem axle chassis
Hazmat charge: $45 flatApplies where contaminated residue or chemicals are involved
Intake condition: Dumped, flushed and certified cleanCleaning is the operator's responsibility, in writing, before delivery

Last verified July 29, 2026

A combination sewer cleaner is the most complicated body in a municipal yard. It is a vacuum vessel, a pressure washer, a water storage system and a crane, all mounted to one chassis and all working at once. When something structural goes wrong, four systems have to be considered before a torch is lit.

The wear pattern is unlike anything else here. Debris arrives in a high velocity stream of water, grit, sand and whatever else was in the line, and it hits the inside of the body in the same place every time. That is not corrosion and it is not impact. It is erosion, and it thins a shell wall from the inside while the outside stays painted and presentable.

Disambiguation

Make sure this is the right page

Note

A combination sewer cleaner carries a debris body, a water tank and a boom. A hydro excavator is the same idea aimed at digging. A water tanker carries potable or construction water and nothing else. The debris body work below applies to the first two.

Erosion is the failure mode, not rust

Debris enters the body in a high velocity stream through a fixed inlet, which means the same patch of shell gets sandblasted every operating hour. That is erosion rather than corrosion, and it behaves differently: it is localized, it is predictable, and it happens entirely on the inside face where nobody looks.

The practical consequence is that these bodies fail suddenly from the operator's point of view. There is no rust bloom giving warning, just a shell that reads sound from the walkway until a weep appears. Districts that map the impingement area and check its thickness on a schedule get years of notice. Those that wait get a leaking vessel mid job.

Impingement area: fixed by the inlet geometry, wears fastest
Loss is internal, so external paint gives no warning
Wear plate protection can be added where a shell has thinned
Thickness checks on a schedule are the only real early warning

The tailgate ring is a sealing surface

For the body to hold vacuum, the tailgate has to seal against a machined ring. Debris caught between the faces during closing scores that ring, residue left behind corrodes it, and once the face is damaged the machine loses suction efficiency. Operators report it as a blower or a hose problem because that is where the symptom seems to live.

Repairing it means treating the ring as a machined surface rather than a flange to weld on. We assess the face, restore or replace the affected section, address the locking bar geometry that holds the tailgate against it, and rebuild the hinge bores that have let the gate hang crooked in the first place.

Assess ring face condition all the way around with the gate raised
Check hinge bore ovality, because a crooked gate scores a ring
Restore or replace the affected ring section
Reset locking bar geometry and verify the gate closes evenly

Boom rotation mounts and moment reversal

The boom holds a heavy suction tube out over a manhole and swings it while loaded. Each swing reverses the moment on the rotation bearing's pedestal, which is welded to the front of the debris body or to its subframe. Bearings themselves are rarely the failure. The weld line under them is.

We inspect that weld line from every accessible angle with dye penetrant, and where the bearing has to come off for access we coordinate with the equipment service provider rather than pulling it ourselves. Reinforcement is designed to spread load into the body structure rather than to thicken the crack that has already formed.

Before you proceed

A boom that has developed a knock at the start or end of a swing is worth inspecting at the pedestal rather than at the bearing. In our bays the crack is under the bearing far more often than the bearing is worn out.

We do not enter a debris body

This is the firmest position on this page. A debris body is a confined space with a biological and chemical hazard history, and nothing about a collision and body shop makes it the right organization to enter one. We do not send a technician inside a tank under any circumstances, regardless of how recently it was cleaned.

Repairs are therefore planned from the outside: we cut and let in from the exterior, we use borescopes and thickness gauges instead of eyes inside the vessel, and where a job genuinely cannot be done externally, the district arranges a specialist contractor for the interior portion. Units also arrive dumped, flushed and certified clean in writing before we open anything at all.

A thousand gallons moving on every corner

Water tanks on a combination unit hold well over a thousand gallons, mounted low along the body sides and strapped into fabricated cradles. That mass sloshes at every turn and stop, and the straps corrode at the exact points where they contact the tank and their own mounting. When one lets go the tank shifts, and it takes plumbing and occasionally a fender with it.

We rebuild cradles and straps in new material with proper isolation, repair the plumbing and mounting we disturb, and pressure test before release. Jetter pump and blower system work belongs to the equipment service provider, and the estimate states which items sit on which side of that line.

Scheduling around a district's line cleaning program

Sewer maintenance is a scheduled program with a published cycle, which makes these units far easier to plan around than emergency vehicles. Districts usually know which weeks a unit can be spared, and we book the wave against that rather than against our own bay availability.

Where a district runs a single combination unit, that changes the calculus completely and we say so at estimate stage. On a sole unit we order every part before intake and we do not start until the parts are here, because a district with no cleaning capability for three weeks is a district with a backlog it will spend a season clearing.

Turnaround, cleaning certificates and intake

A local erosion repair is generally four to nine shop days. Ring and hinge work runs one to three weeks. A boom pedestal repair with equipment coordination is two to four weeks. Water tank and reel frame work is three to eight days depending on how much plumbing has to come off.

Every unit arrives dumped, flushed and with a cleaning certificate from the district or its contractor. All work is performed in shop at the Yorba Linda facility, and no part of this business is a mobile repair service or a roadside operation. Districts covering Rancho Santa Margarita run these units up the 241 to the 91 like the rest of the heavy fleet.

Construction

How a water and sewer is built

Construction and dimensions
System	What it is
Wall system	Cylindrical or elliptical steel debris body designed for vacuum and dump duty, with a hinged tailgate carrying a machined sealing ring and locking bar mechanism, plus cyclone separators, aluminum or poly water tanks in fabricated cradles and a hose reel frame at the front
Roof system	Body top with inspection and vacuum breaker fittings, walkway and railing structure, and a telescoping or articulating boom mounted at a rotation bearing on a pedestal at the front of the debris body
Chassis	Tandem axle severe service chassis: Freightliner 114SD, Peterbilt 348, International HV or Mack Granite, with an auxiliary blower and water pump system driven from the chassis or a separate engine, and hydraulics for boom, reel and tailgate functions
Typical length	30 to 38 feet
Typical GVWR	54,000 to 66,000 lb

Failures

What typically goes wrong on this vehicle

Debris body shell thinning where the inlet stream lands

Material enters the body at high velocity through a fixed inlet and impinges on the same area of shell every hour of operation. Sand and grit in that stream erode steel steadily. Because the loss happens on the inside, the first external sign is often a weep or a pinhole in a shell that looks entirely sound from the walkway.

How we repair it

Tailgate sealing ring face damage and vacuum loss

The tailgate seals against a machined ring so the body can hold vacuum, and that ring gets scored by debris caught between the faces during closing, then corroded by whatever residue stays behind. Once the ring face is damaged the body stops holding vacuum efficiently, which operators experience as a machine that has lost suction.

How we repair it

Cracking at the boom rotation bearing pedestal mount

The boom carries a heavy suction tube out over a manhole and swings it under load, and the rotation bearing sits on a pedestal welded to the front of the debris body or its subframe. Every swing is a moment reversal on that mounting, so cracks appear at its weld line rather than in the bearing itself.

How we repair it

Water tank cradle and strap failure

These trucks carry over a thousand gallons of water in tanks strapped low along the sides, and that mass sloshes on every corner. Straps and cradles corrode where they contact the tank and where they mount, then a strap lets go and the tank moves, taking plumbing and sometimes a fender with it.

How we repair it

Hose reel frame, cab guard and railing damage

The reel frame carries hundreds of feet of hose and lives at the front of the body where crews climb, hang tools and occasionally reverse a truck into a manhole cover stand. Railings and cab guards on top take branch strikes on residential streets. Both are welded assemblies that crack at their mounts rather than bending in the middle.

How we repair it

Cost

What common jobs run on this vehicle

Debris body shell section and internal repair

$750 to $20,000+

5 to 80 labor hours at $210 per hour, body and paint.

Body supplies at $5 per body hour.
Hazmat and disposal $45 flat when chemicals, refrigerant or LP is involved.
Parts at $100 or less carry 100 percent markup. Parts over $100 carry 35 percent. Special order parts require a full non refundable deposit at order.
Sales tax of 7.75 percent applies to parts and materials. Labor is not taxed.
A 50 percent deposit is taken at authorization on any job over $2,000, with an additional 25 percent when parts arrive on any job over $10,000. Final balance is due at pickup.
A local erosion patch is a few days. Letting in a full impingement area with wear plate protection is a multi week job on a vessel this size.

Tailgate ring, locking bar and hinge rebuild

$2,500 to $14,000+

12 to 60 labor hours at $210 per hour, body and paint.

Body supplies at $5 per body hour.
Parts at $100 or less carry 100 percent markup. Parts over $100 carry 35 percent. Special order parts require a full non refundable deposit at order.
Sales tax of 7.75 percent applies to parts and materials. Labor is not taxed.
A 50 percent deposit is taken at authorization on any job over $2,000, with an additional 25 percent when parts arrive on any job over $10,000. Final balance is due at pickup.

Boom pedestal and rotation mount repair

$3,000 to $18,000+

15 to 80 labor hours at $210 per hour, body and paint.

Body supplies at $5 per body hour.
Parts at $100 or less carry 100 percent markup. Parts over $100 carry 35 percent. Special order parts require a full non refundable deposit at order.
Sales tax of 7.75 percent applies to parts and materials. Labor is not taxed.
A 50 percent deposit is taken at authorization on any job over $2,000, with an additional 25 percent when parts arrive on any job over $10,000. Final balance is due at pickup.

Water tank cradle, strap and hose reel frame repair

$750 to $7,500+

5 to 35 labor hours at $210 per hour, body and paint.

Parts at $100 or less carry 100 percent markup. Parts over $100 carry 35 percent. Special order parts require a full non refundable deposit at order.
Sales tax of 7.75 percent applies to parts and materials. Labor is not taxed.
A 50 percent deposit is taken at authorization on any job over $2,000, with an additional 25 percent when parts arrive on any job over $10,000. Final balance is due at pickup.

Cab guard, walkway and railing repair

$1,500 to $10,000+

8 to 45 labor hours at $210 per hour, body and paint.

Body supplies at $5 per body hour.
Parts at $100 or less carry 100 percent markup. Parts over $100 carry 35 percent. Special order parts require a full non refundable deposit at order.
Sales tax of 7.75 percent applies to parts and materials. Labor is not taxed.
A 50 percent deposit is taken at authorization on any job over $2,000, with an additional 25 percent when parts arrive on any job over $10,000. Final balance is due at pickup.

Shop fit

Will it fit in the shop?

A 38 foot combination unit is one of the largest vehicles we take, and it works here because of door height and floor space rather than lift capacity: at 66,000 lb it stays on the slab, and we need vertical room to raise a tailgate and access the ring face. Units arrive dumped, flushed and certified clean in writing. We do not perform confined space entry into a debris body under any circumstances, so any repair requiring interior access is planned around external cutting and a district supplied cleaning certificate.

Claim

Insurance considerations for this vehicle

Erosion inside a debris body is consumption, not a loss, and districts that budget shell renewal at an interval avoid the far worse outcome of finding it as a leak during a job. No carrier participates in that work.
Collision claims on these units usually involve the rear of the truck at a work site or a boom contacting a structure. Boom contact needs the equipment manufacturer's assessment in the file alongside our structural scope, because the two together are the real cost.
Where a body is being repaired after a contamination incident, the district's own disposal documentation matters more to the claim than ours. We add the $45 flat hazmat charge where contaminated residue is involved and we document what we handled.

Appendix

Appendix: questions and answers

Our debris body developed a weep with no visible rust. How?: Erosion, not corrosion. Debris enters at high velocity through a fixed inlet and sandblasts the same patch of shell every operating hour, thinning it from the inside. The outside stays painted and sound looking until a pinhole appears. We repair the area and can add wear plate protection where the shell has thinned.
The machine has lost suction and the blower checks out. What next?: Look at the tailgate sealing ring. The body holds vacuum against a machined ring face, and debris caught during closing scores it while residue corrodes it. We assess the ring with the gate raised, check hinge bore ovality since a crooked gate scores a ring, then restore the face and reset locking bar geometry.
There is a knock at the start of every boom swing. Bearing or mount?: In our experience the mount, far more often than the bearing. Each swing reverses the moment on the pedestal welded to the body or subframe, so cracks form at that weld line. We dye penetrant the full accessible weld line and coordinate with the equipment service provider if the bearing must come off for access.
Will your technicians go inside the debris tank to weld?: No, under no circumstances and regardless of how recently it was cleaned. A debris body is a confined space with a biological and chemical hazard history, and a collision shop is the wrong organization to enter one. We repair from the outside using borescopes and thickness gauges, or the district arranges a specialist for interior work.
What condition does the unit have to arrive in?: Dumped, flushed and accompanied by a cleaning certificate from the district or its contractor, in writing, before we open anything. A $45 flat hazmat and disposal charge applies where contaminated residue or chemicals are involved in the work itself. On a properly cleaned unit that generally does not arise.
We only have one combination unit. How do you handle that?: We order every part before intake and do not start until the parts are physically here, so the truck is never sitting in our building waiting for a delivery. We also say plainly at estimate stage how many days the unit will be down, because a district with no cleaning capability builds a backlog fast.

Next step

Open a file on this repair

Tell us the vehicle, what happened and whether a claim is open. We will tell you what the scope looks like and what it takes to get you back on the road.

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