Overview
High-temperature seal kit for the HydraMaster Hydra Pump II. HydraMaster part number 000-078-158, listed as Kit, Hydra Pump 2, hi temp. seal kit.
The "hot" in the name is the point. These are the seals specified for the solution temperatures a truckmount actually runs at, and they are not the same as a general-purpose seal set.
What it fits
HydraMaster's suggested spares schedule lists it against:
- HydraMaster Boxxer 421
- HydraMaster SpitFire 3.2
It is specified by pump rather than by machine, so it suits any machine running a Hydra Pump II. Check the pump, not the machine.
The three Hydra Pump II service items
- 078-158 — high-temperature seal kit (this part)
- 078-159 — valve kit (also covers the Hydra Pump 5)
- 147-009 — crankcase oil seal, 3 per pump
A pump that has been in service long enough to need seals has usually earned a valve kit as well. Doing them together means the pump comes apart once.
When to fit it
The symptoms of worn high-pressure seals are all pressure symptoms: pressure that will not reach the set point, pressure that reads at rest and falls away under trigger, or a pump that has become noticeably noisier under load.
Water leaking from the weep holes between the water end and the crankcase is the unambiguous sign. Do not run a pump that is weeping — you are about to put water in the crankcase.
Seals in hot service harden as much as they wear. A pump on a machine running high solution temperature will want seals sooner than the same pump running cooler, at the same hours.
Fitting advice
Inspect the plungers before you fit new seals. Scoring, pitting or a dull worn band on a plunger will chew through a new seal set in a fraction of its normal life. Replacing plungers costs more than seals; replacing seals twice costs more than both.
Cleanliness matters more here than almost anywhere else on the machine. One piece of grit under a seal lip is a leak.
Follow HydraMaster's torque figures on reassembly. Uneven clamping on a water end distorts the seals and causes exactly the fault you are repairing.
Frequently asked questions
Is this the same as the oil seal?
No. 147-009 is the crankcase oil seal, three per pump. This kit is the water-end high-temperature seals.
Should I do the valves at the same time?
Usually yes. The valve kit is 078-159, and doing both means one strip-down rather than two.
What is in the kit?
HydraMaster does not itemise the contents in the documentation we hold, and we are not going to list contents we cannot verify. Ask us if you need to know before ordering.
Will a standard seal kit do?
Not for hot service. HydraMaster specify a high-temperature kit for a reason.
Send us your pump details and what the machine is doing and we will work out whether you need seals, valves, or both before you order.
