Spline, lining OD and cover numbers beat a photo of the cover

Identifying a tractor or loader clutch is a measurement and stamping job. Diameter alone is not an identity. Spline, lining OD, hub length, cover tag and the flywheel bolt circle together decide whether the replacement will slide on, clamp up and release. This page is the practical sequence before you open the clutch category or send a photo to sales.

Do this before the assembly is unrecognisable

Photograph the cover casting number, any OEM tag, the hub face and the flywheel side of the plate. Count spline teeth; measure major diameter of the spline and the lining outside diameter. Note whether the plate is sprung or rigid, organic or cerametallic, and whether there is one plate or two. If the machine still runs, record pedal free play and whether the PTO clutch is a separate pack.

Spline and lining are not interchangeable

A 28.6 mm spline with 21 teeth is not a 24-tooth hub at the same rough size. Lining OD that is 2 mm small will still bolt up and will not last. Hub length that is wrong will not sit in the cover. Write the three numbers on the job card. If the old plate is glazed past reading, use the parts book line for that make and model rather than a 'popular size' chart.

Cover load and flywheel

Cover identification is the casting or the OEM number on the tag, plus the flywheel step and bolt circle. A cover from a similar horsepower tractor can have a different clamp load. Do not mix a light cover with a cerametallic plate 'because it is stronger' — the flywheel and damper were designed as a set. Inspect the flywheel for heat cracks and for a step; machining limits belong in the same order as the clutch.

Photograph cover tag, hub and lining before strip-down
Count spline teeth and measure lining OD and hub length
Note single vs dual plate and facing material
Copy flywheel bolt circle and any step dimension
Send make, model and the numbers to SEROC if the fit is unpublished

Actuation type belongs on the same card

Hydraulic, cable and mechanical release are not interchangeable even when the plate looks right. Note slave or cable, fork wear, and whether free play was adjustable. A cover from a similar horsepower tractor can have a different clamp load. Do not mix a light cover with a cerametallic plate 'because it is stronger' — flywheel and damper were designed as a set. If the flywheel step is worn past the book, the clutch identity is still valid but the flywheel is a second line on the order.

When two numbers disagree

If the plate stamp and the parts book disagree, do not average them. Send both to sales with the machine serial. A dual-plate pack is identified as a pack. PTO clutches on some tractors are a separate pack behind the gearbox; write travel or PTO on the job card before anyone walks to the shelf. When the numbers are on paper, open the clutch category or model search. OEM mark first, photo second.

Return to the clutch pillar for duty and actuation, and to symptoms if you are not sure the clutch is the failed part. Identification is finished when spline, lining OD, hub length and cover tag are written down — not when a cover photograph looks familiar.

Workshop sequence

1. Photograph cover tag, hub and lining before anything is unbolted. 2. Count spline teeth; measure major diameter, lining OD and hub length. 3. Note single versus dual plate and organic versus cerametallic. 4. Copy flywheel bolt circle and any step. 5. Write travel or PTO, and hydraulic versus cable versus mechanical. 6. If the stamp and the parts book disagree, send both with the serial — do not average. 7. Only then open the clutch category or email sales. A similar horsepower tractor is not an identity. A 2 mm lining error will still bolt up and will not last. Hub length that is wrong will not sit in the cover. Keep grease off the linings while you measure. This sequence is the HowTo for this page; installation and symptoms are separate jobs.

What 'close enough' costs

A lining that is a few millimetres small still clamps and still glazes. A spline that is 'about 21 teeth' either slides or destroys the hub. A dual-plate cover with a single plate is not a temporary fix. Count, measure, write, then order. If the old plate is unreadable, the parts book for that serial is the identity — not a popular-size chart from another market. Keep the flywheel step in the same notes as the clutch so machining limits are not a surprise after the tractor is split. That is the whole job of this page.