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Cat 1 or cat 2 hydraulic top link

Updated: 21.10.2026

The listing says category 1, and you have never put a calliper on the top pin. Cat 1 or cat 2 hydraulic top link is a question of pin diameter and clevis width at both ends, not of a word in the title. You should finish this page knowing which pin you have, and why a 3/8 in line on a category 1 title cannot be right if UK parts pages are your guide. The rows themselves are the [hydraulic top link comparison](/hub/garden-tools/hydraulic-top-link). This is the Products Compared editorial team, using UK parts pages and ISO's category standard, not a measured sample of these cylinders. A qualifying purchase can earn a commission at no extra cost to you.

The listing says category 1, and you have never put a calliper on the top pin. Cat 1 or cat 2 hydraulic top link is a question of pin diameter and clevis width at both ends, not of a word in the title.

Our top picks

Solarhome Solarhome cat 1 top link, 18 1/8–26 3/8 in

Best overall

Solarhome Solarhome cat 1 top link, 18 1/8–26 3/8 in
7.0/10about £198.08
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bonbo bonbo cat 1 top link, 20 7/8–31 7/8 in

Best value

bonbo bonbo cat 1 top link, 20 7/8–31 7/8 in
6.5/10about £209.32
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Solarhome Solarhome cat 2 top link, 22 3/8–33 1/2 in

Alternative

Solarhome Solarhome cat 2 top link, 22 3/8–33 1/2 in
6.3/10about £268.56
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On this page
  1. 1.The two pin sizes
  2. 2.Clevis width is the other half
  3. 3.What these listings print
  4. 4.Mixed ends

The two pin sizes

A category 1 top-link pin is about 19 mm, which is 3/4 in. A category 2 top-link pin is about 25 mm, which is 1 in. Malpas Online's linkage page states those figures. Agri-Linc sells category 1 pins at 19 mm and category 2 pins at 25 mm. When a shop guide and a pin disagree, the pin wins. ISO 730:2009 sets rear-linkage categories against tractor power. It does not mean you can look up kilowatts and skip the calliper. Measure the pin that is in the tractor now, and measure the hole in the implement. The lower-link pin is a different part. On the Malpas table the lower pins are about 22 mm for category 1 and about 29 mm for category 2. If you measure the lift-arm pin and order a top link to that number, you will buy a cylinder that will not enter the top hitch.

Clevis width is the other half

A correct pin can still refuse the bracket. The ball, or the clevis, has to pass between the lugs on the tractor and on the implement. Listings in this set that mention a width say 1 3/4 in on the category 2 bullets. That figure is a claim next to a 1 in hole. It is not a measurement of your lugs. Non-UK reviews on those pages say the ball turned up wider than 1 3/4 in, about 2 in in some notes, and that grinding was the way they made it fit. You should not plan to grind. A bush can reduce the free play of a pin that is slightly smaller than the hole. It does not make a wide ball thinner. Measure both ends. A pin that fits the tractor and a ball that will not enter the implement is still a failed fit.
Solarhome Solarhome cat 1 top link, 18 1/8–26 3/8 in

Testsieger

Solarhome Solarhome cat 1 top link, 18 1/8–26 3/8 in
7.0/10about £198.08
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What these listings print

Five category 1 titles in this set state a 3/8 in pin: the short sixcow pages, the short Solarhome page, the bonbo longer page, and the KSQOON page. Three-eighths of an inch is 9.5 mm. A category 1 pin on the UK pages above is about 19 mm. The comparison table keeps the figure as printed. It does not correct it to 19 mm, because nobody has measured the pin in the box. One Solarhome title says category 1-1 and a short length, and a bullet on the same page says category 2 with 1 in holes and a 1 3/4 in ball width. That is not a hybrid hitch. The only category 2 page whose title and bullet share one length still only claims 1 in holes. Solimeta's longer category 1 page and the SPH320032 short page print no pin and no hole. Absence is not a quiet confirmation of 19 mm.

Mixed ends

A real mixed hitch exists. Agri-Linc sells a hydraulic top-link kit with a category 1 end at the tractor and a category 2 end at the implement. That is a product, not a mistake, when the tractor pin is 19 mm and the implement lug is built for 25 mm. You only order it after both sides have been measured. This amazon set does not title a clean category 1-2 cylinder. A bullet that says category 2 on a category 1 title is a contradiction, not a mixed-end kit. After the pins and the widths match, length and the remote are the next decisions, and they belong on the hydraulic top link buying guide. A category 2 pin in a category 1 hole will not enter. A category 1 pin in a category 2 hole will rattle. The two calliper readings pick the category.

Common questions

What diameter is a category 1 top-link pin?
About 19 mm, or 3/4 in, on Malpas, Agri-Linc, Emmark and Kramp. Measure the pin in your top hitch rather than trusting the tractor model. A listing that says category 1 and then says 3/8 in is not stating this 19 mm pin.
What diameter is a category 2 top-link pin?
About 25 mm, or 1 in, on the same UK parts pages. Category 2 bullets in this set that mention holes say 1 in, which is the right family of number, and they still need a check against your lugs.
Why does a listing say 3/8 in on a category 1 cylinder?
The pages print it. Five category 1 titles in this set do. Three-eighths of an inch is 9.5 mm, and the usual UK category 1 top pin is about 19 mm. The table leaves 3/8 in as the seller's figure. You compare it with a calliper. Do not assume the seller meant 3/4 in.
Can one end be category 1 and the other category 2?
Yes, when you measured that difference. Trade kits exist with a category 1 tractor end and a category 2 implement end. This amazon set does not label a clean mixed pair. A bullet that swaps category and length on a category 1 title is a clash, not a hybrid specification.
Can I bush a category 2 pin down to category 1?
A bush can take up a small difference in pin diameter. It does not fix a ball or a clevis that is wider than the lugs. If the widths do not match, return the cylinder.

Related pages

Best hydraulic top link

Hydraulic top link

Hydraulic top link buying guide for pin and length

How to fit a hydraulic top link and pressure-test it

Hydraulic top link leaking, drift and a cracked weld

Sources

Public UK and standards sources used for hitch category, couplers and hydraulic safety. Listing prices, stars and review counts are the amazon.co.uk captures for this comparison.

  1. HSE — High-pressure fluid injection hazards (retrieved 21.10.2026)
  2. HSE — Hydraulic injection injury (retrieved 21.10.2026)
  3. HSE INDG185 — Using tractors safely (retrieved 21.10.2026)
  4. ISO 730:2009 — Agricultural wheeled tractors, rear-mounted three-point linkage (retrieved 21.10.2026)
  5. Anglo Agriparts — 3 point linkage (retrieved 21.10.2026)
  6. ISO 5675:1992 — Agricultural tractors and machinery, general purpose quick-action hydraulic couplers (retrieved 21.10.2026)
  7. BFPA — Hydraulic injection injury in the field (retrieved 21.10.2026)
  8. Consumer Rights Act 2015 (retrieved 21.10.2026)