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Hydraulic Ram Seals
IronDino333, on the Heavy Equipment Forum has been carrying out seal replacements on his MM30SR and sent me information on the seal sizes etc which I’ve posted below. As he says this information might be useful to someone.
Boom:
It's an 85mm bore with 45mm rod.
wiper/dust seal - 45-57-7
U-cup/rod seal - 45-65-13 ( I couldn't find this size and ended up ordering a 12mm and making a 1mm shim)
2 O-rings - 80mm ID x 3mm C.S.
1 O-ring - 85mm ID x 3.2mm C.S.
2 bearings/wear rings - 85mm X 15mm X 4mm
I did not replace the Piston seal as it was still in good shape - no real way to get it off to measure without destroying it unfortunately.
Arm:
It's a 75mm bore with 45mm rod.
wiper/dust seal - 45-57-7
U-cup/rod seal - 45-60-9
2 O-rings - 70mm ID x 3mm C.S.
1 O-ring - 75mm ID x 3.2mm C.S.
2 bearings/wear rings - 75X11.8X4 (I measured 75X12X4 but 11.8 was all I could order and will work)
Piston seal - 59.50 mm x 75 mm x 6.30 mm
Bucket:
It's a 75mm bore with 40mm rod.
wiper/dust seal - 40-52-7
U-cup/rod seal - 40-55-9
2 O-rings - 70mm ID x 3mm C.S.
1 O-ring - 75mm ID x 3.2mm C.S.
2 bearings/wear rings - 75X11.8X4 (I measured 75X12X4 but 11.8 was all I could order and will work)
Piston seal - 59.50 mm x 75 mm x 6.30 mm
I reused the backup rings but those numbers would correspond to the O-ring sizes and if you give a shop the O-ring sizes they can look them up for you. You only need these for the sets of 2 O-rings for each - the 3rd O-ring just seals the gland nut near the face and has no backup ring.
These seals were all pretty simple to change without any special tools - 2 of the gland nuts are a 2 piece design that makes it easy to swap the rod seal - so if you find them leaking you'll definitely save a lot doing the job yourself.
Cheers,
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