Tractor Mirror Arm Snapped? Knock-Back Arms, Brackets and Reach

A hedge clips your tractor mirror and snaps the arm, the bracket cracks, or the mirror simply won’t stay where you set it. Most fixes come down to the right arm, a solid mounting point and sensible reach.

PartsForMachines lists 66 Ashtree mirror accessories, from arms and knock-back arms to brackets, heating elements and switches, in its Mirror Accessories range.

Hedges Keep Snapping My Mirror: Do I Need a Knock-Back Arm?

Yes, if branches, walls or gateposts hit your mirror often. A knock-back arm lets the arm and head swing back when something strikes them, and you then push it back into place, so a knock is less likely to break the mirror for good.

That suits forestry, narrow lanes and busy sites. The S1500-64/44 knock-back mirror arm spans 640mm wide by 442mm high on a 28mm tube; the S1500-78/63 gives 780mm by 630mm. For a little give rather than a full fold, the S1700-64/44 arm flexes a controlled amount to protect the mirror if it is struck.

My Mirror Bracket Broke: Where Should the New One Go?

Bolt the new bracket to a solid mounting point on the cab, and use the bracket made for your arm. Don’t drill or weld a rollover protective structure (ROPS): holes or welds can stop it protecting you in an overturn.

For Desmo and S900 arms with a 16mm tube, the Y2089 mounting bracket is a 77mm by 65mm plate with four 7mm holes. If you want to drill a loader bracket or another part of the machine, check the operator’s handbook first. And if hedges broke the old bracket, pair the new one with a knock-back arm.

How Long Should a Mirror Arm Be on a Tractor or Plant Machine?

Choose an arm only long enough to let you see clearly past the widest point of the machine or the implement behind it. Measure from the mounting point to where the mirror head needs to sit, both outwards and down, and note the tube diameter of the old arm.

Sizes vary a lot. The S901 measures 198mm by 152mm on a 16mm tube, the S1550-16/55 long-drop FlexArm gives 160mm across with a 550mm drop on a 28mm tube, and the S1550-85/70H spans 850mm by 700mm. Any length beyond what you need just sticks out further for hedges and gateposts to catch.

Mirror Won’t Stay Where I Set It: Repair the Arm or Replace It?

Try re-setting and re-tightening first, renew any sheared bolts, and replace the arm itself if it is bent or cracked. Sit in the driver’s seat, set the arm to the angle you need, then tighten the bracket bolt so it holds, to the torque in the fitting instructions where one is given.

Check the joint for wear, too. Ashtree gives its S900 arms two sets of opposing zinc teeth to cut wear as the arm indexes. If yours is past saving, the S901 FlexArm is a 16mm-tube replacement; compare its price with the time a repair would take.

What Should I Check Before I Order?

the tube diameter of your arm (16, 19, 25 or 28mm, for example) and the bracket it needs
the width and drop from the mounting point to where the head must sit
the hole pattern and spacing on the cab, plate or old bracket
whether the machine works along hedges, trees or tight sites, where a knock-back arm helps
a 12V or 24V system, for heating elements and mirror switches

Browse the Mirror Accessories range, or contact the PartsForMachines team by WhatsApp, telephone or email with photos of the old arm and bracket and the machine model.

Product options, delivery options and returns terms are shown on each product page. A 30-day return policy applies to eligible items.

Frequently Asked Questions

Can I fit a tractor mirror arm without drilling?

Often, yes, if the cab already has mounting points. S900 arms have three M6 threaded holes at 45mm or 60mm centres, so they can bolt to matching holes, or the Y2089 bracket mounts them externally.

Is it safe to drill a ROPS frame to mount a mirror?

No. Drilling holes in a ROPS, or welding to it, can stop it protecting you in an overturn. Use the cab’s own mounting points instead, and ask the machine maker before altering the frame in any way.

Should I take the mirror off when working off-road?

Yes, if it keeps getting hit; a removable arm makes that quick. The Y3123 sliding wedge is used with the S1700 range for a removable arm, together with the Y3124 four-hole bracket. Refit and adjust the mirror before you drive on the road.

Can I replace just the electrical plug on my mirror?

For some mirrors, yes. The Y3098, for example, is a 2-pin male plug made for the M926CEH mirror. Check the model number on your mirror and match the plug’s pin count before you order.

Can I add a heater to stop my mirror misting or icing up?

Yes. A heating element bonds to the back of the mirror glass and helps stop condensation and frost building up. Match the size and voltage: the Y2619 is 250 x 145mm at 24V, and the Y2619-12 is the 12V version.

Will a 12V mirror switch work on a 24V machine?

Pick the switch for your system voltage. The Y2677-12 (12V) and Y2677-24 (24V) are 4-way switches for both sides with a 2-metre cable. The Y2678 runs on 12V or 24V and controls two twin-lens mirrors.

Can I add a mirror to see a trailer or implement behind me?

Yes. A rearview extension such as the AVS-FRE20/25, about 200 x 250mm, adds cover of trailers and implements the standard mirror may miss. It mounts to suitable arms or brackets alongside your existing mirrors.

How tight should the mirror arm bolts be?

Use the torque given in the fitting instructions for your arm or mirror kit, where one is given. The figure varies from one kit to another, so look it up rather than guessing; if there is none, send our team the arm’s part number.