Thousands of hours subjected to bouncing backsides, grubby overalls and flatulence can take its toll on a tractor seat.

But considering it’s such a crucial contributor to driver comfort, this cushioned perch is often left to get into a terrible state before it gets a whiff of TLC.

Thankfully, when the time does come, there are plenty of spare parts available to get dog-eared upholstery and pummelled suspension back into prime condition.

And, if the whole thing is just too far gone, there are several aftermarket replacements available to suit various budgets.

See also: What to look for when buying and fitting a tractor dashcam

To help diagnose some common problems and pinpoint the parts required to put them right, we’ve drafted in the help of Leicestershire-based specialist Capital Seating.

The firm supplies spares for major brands, as well as offering an in-house repair and retrimming service at its headquarters in Leicester.

© James Andrews

Most of the seats fitted in new tractors are made by Grammer, so we are mainly focussing on its models in this article.

However, the aftermarket sector is more varied, with older tractors and self-propelled kit being fitted with replacements from the likes of United Seats and KAB – see “Replacement seat options”.

Regardless of the brand, they all work in roughly the same way and use a similar collection of parts.

Cushions and upholstery

Repeated sliding in and out of seats will eventually leave the fabric in tatters, followed closely by the foam padding underneath.

As the fabric is bonded to the foam, it is difficult to do a tidy reupholstery job and get the cushions back to their original condition. However, various brand-specific fabric covers are available, which hide most sins.

If the cushions have had it, original-spec replacements are available in a range of fabrics to match different interiors, with prices ranging from £90 to £150.

To keep seats looking fresh for longer, there’s always the option of fitting waterproof protective covers. Generic versions tend to fit where they touch and soon bunch up into an uncomfortable mess.

If going down this route it’s worth shelling out a bit extra for something tailor-made. A set for driver and passenger seats can usually be found for about £120.

Shock absorber

Both mechanical and air seats are fitted with a shock absorber to slow the compression and extension of the spring.

They play a crucial role in the function of the suspension, and if they fail the seat will often end up bouncing like an uncontrollable pogo stick.

Replacements generally cost £50 to £80 and are relatively straightforward to fit.

© James Andrews

Rollers and bearings

As a tractor seat moves up and down, it is supported by a swinging structure that looks a bit like a scissor lift.

At the top of this there are rollers and bearings that slide in a channel, and these will eventually wear out. The trick is to catch them before they disintegrate and damage the channels, making it a far more serious repair job.

If a seat is used for long periods with trashed rollers and bearings, it can get to the point where it’s easier to buy a new base rather than try to patch it up – see “Replacement base”, below.

Prices for rollers and bearings vary from as little as £5 to £45 depending on the model of seat.

© James Andrews

Air spring

Pneumatic seats have an internal air bag that takes the place of the conventional steel springs in cheaper mechanical versions.

These can fail and refuse to hold air, meaning a replacement is required at a cost of £85 to £140.

Before committing to buy one, it’s worth double checking that the leak is in the air bag and not another part of the system.

© James Andrews

Level control unit

If an air seat inflates and deflates as it should, but doesn’t settle at the desired height, the level control unit could be at fault.

These have a fairly sophisticated mechanism with a reel of belt to return the seat to its set position. They mount to the rear of the suspension system and replacements cost £160 to £220.

© James Andrews

Compressor

Should a seat fail to pump up at all then it is likely the compressor is the component at fault. This is fitted on the base and is usually held in with cable ties.

They tend to cost between £80 and £160 and fitting is straightforward once the rubber surround has been lowered.

Replacement base

If the suspension system is too far gone, but the seat is still in decent condition, it might be worth investing in a new base.

These come in both mechanical and air-suspended form, so it’s possible to upgrade an old coil-spring seat to air, without buying a completely new setup.

Mechanical bases cost about £250 and factor in between £470 and £1,000 for one with air suspension, depending on how sophisticated it is.

*When doing any work on the suspension it’s important to place a block in the scissor arrangement to prevent it dropping and trapping your fingers.

Complete replacement seat options

Grammer Maximo Dynamic

© Capital Seating

Grammer’s Maximo seat is an original fitment in many tractors from mainstream brands such as John Deere, New Holland and Massey Ferguson.

Like most of the firm’s seats, it comes in a modular setup, meaning there is a huge array of specs on offer.

At its most basic, the Maximo has a mechanically sprung base and few adjustments, while the top-spec versions float on automatically adjusting air bags for fore-aft damping and boast luxuries such as climate control.

The Maximo Dynamic is a popular model that sits roughly in the middle of the range but is still of decent quality.

This comes with a fancy air suspension assembly that aims to reduce vibrations, as well as a one-touch system for adjusting the seat to the desired position.

It also includes extras such as pneumatic lumbar support, swivel, adjustable seat cushion angle and length, and a heating element.

Maximo Dynamic guide price: £2,200 retail – significant discounts are available

KAB Sciox Premium

© Capital Seating

The air suspended Sciox seat from KAB comes in a range of specs to suit different budgets and specs of tractor.

Entry-level versions offer basic adjustments and no headrests, making them suitable for older tractors that don’t do too many hours.

But climbing through the spec levels brings in features such as variable damping and adjustable lumbar support.

The all-singing, all-dancing Sciox Premium is the top-spec model, which comes with luxuries such as heating and cooling, a leather-and-fabric covering, plus myriad adjustments for the suspension system and cushions.

Sciox Premium guide price: £2,150

United Seats Rancher Pro

© Capital Seating

The Rancher Pro is the top-of-the-range pneumatic option from United Seats, which comes with lumbar support, an adjustable backrest and 120mm of suspension travel.

Additional features include a variable damper, a fore/aft isolator and powered weight/height adjustment to suit operators from 50 to 135kg.

There are also multiple settings for seat cushions and the backrest, including a lumbar support, plus a 20deg swivel to give a better rearward view.

For those on a lower budget, there are several simpler versions of the Ranger, with the cheapest offering mechanical suspension.

Ranger Pro guide price: £725