# Service bulletin SIL 799

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

- Type: Service bulletin
- NHTSA id: 10193118
- Published by NHTSA: 2021\-05\-13
- Manufacturer's number: SIL 799
- Manufacturer's date: 2021\-05\-12
- NHTSA component: EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; SERVICE BRAKES, AIR:SUPPLY:CHECK VALVE

## NHTSA's summary

A check valve is installed in the control valve for the front bumper winch on certain DC series derricks built from January 2016 through February 2021. Altec has discovered that the check valve has the potential for failure. When the check valve fails, the internal spring can dislodge from the housing and enter the hydraulic system. The hydraulic flow can carry it into the digger/winch control valve and cause one of the spools to bind in the closed position, disabling the function. Altec requires the 035240052 check valve to be replaced no later than the next preventive maintenance interval or 90 days from the receipt of this SIL, whichever comes first.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2021/MC-10193118-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2021/MC-10193118-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Brakes, Equipment and accessories, Labels and manuals

## Vehicles listed

- 2016 to 2020 ALTEC DIGGER DERRICK

JSON: [/v1/bulletins/10193118](/v1/bulletins/10193118)

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