Could you describe the reasons for the replacement of clutch boosters? What are the symptoms? What is the VIN of your truck and the part number of the last cluch booster you have installed?
Sorry for the delay,
Could you recheck the VIN, because th number must be 17 character long.
There is one workshop information i suggest to try. Here it is:
Poor metering of clutch, clutch does not separate
Clutch booster does not operate correctly (piston has excessive resistance / is seized) or is leaking
Fit repair parts kit for repairing the clutch booster.
IMPORTANT: Select the repair kit depending on the hydraulic medium:
- either for DOT 4 (brake fluid), WITHOUT sales code IY2
- or for hydraulic fluid as per sheet 345.0 (Pentosin CH 11 S), sales code IY2, green cover
On vehicles with transmission capable of fording (code G39) the cover plate on the clutch booster must be sealed with silicone (e.g. A(NNN) NNN-NNNN10).
Please recheck the VIN, then i will be able to look more closely into this.
Such a fault is not a known failure on these trucks. That is why i recommend to repair the servo according to factory info as a first step. It might be possible that the repair kit is of better quality.
Another possibility is that replacement procedures are not adhered to. I can provide you with these if neccesary.
As i wrote earlier, it would be great to recieve the full VIN of the truck, because i cannot see the transmission/clutch version without it.