Giant LP255 Series, LP123 Series, LP122A-4000 LP122A Series/LP123 - Repair Instructions

LP122A Series/LP123 - Repair Instructions

1.With a 30mm wrench, re- move the six (6) plugs (48) from the valve casing (43). Inspect the o-rings (48A) and replace if necessary.

Remove the complete valve assembly (46A) by thread- ing a 12mm bolt into the spring retainer and pulling straight out.

44A 44 45 48 47

2.To disassemble the valve, screw the bolt into the retainer until the valve plate (45) presses the valve seat (44) out of the spring retainer. Examine all parts and replace if necessary. If the seat doesn’t come out, use a valve puller to remove.

3.Remove the eight (8) hex nuts (49A) with a 19mm wrench. Tap the back of the manifold (43) with a rubber mallet to dislodge and slide off the studs.

5.If there are signs of oil leaking through the plunger oil seals, then replacment is neccessary.For LP122A & LP122A-4000, remove the plunger pipe (29B) before inspecting oil seals (31A & 33).

For the LP123 & LP122A-3100 dissassemble the gear end and push out the seals from the back of the pump.

36A	36	35	35A	35B	39	40	40	41	37
				(LP255 only)					(LP255 only)

4.Remove the seal sleeve (35) from the manifold and/or crank- case. Remove the pressure rings (39&36A), v-sleeves (40&36), support ring (41) and o-rings (35A and 35B in Lp255A only) from the manifold and seal sleeve, respectively. For LP255 only, remove support ring (37). Examine seals carefully and replace if worn. Clean all parts.

29E 29A 29B 29D 29C

6.Inspect surface of plunger pipe (29B) carefully. Remove any chemical or mineral deposits taking care not to damage the surface of the plunger. If plunger pipe is worn, remove the plunger bolt (29C) , plunger pipe (29B) and spacer (29E). Replace worn parts necessary. Note: Always use a new copper gasket (29) when repairing the plunger assembly.

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