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Brake Relay Valve

Brake Relay Valve Kits

Brake booster valve
Improve tractor brakes
Relay Valve Kits


These Kits are designed for tractors built in 2018 and onwards to boost braking pressure being delivered to the trailer following the introduction of new Tractor Mother Regulations (TMR) which came into force from 01.01.2018 and are applicable to all new tractors sold in Europe (including the UK) of all power categories.

Why is New Tractor Braking so Poor?

Part of the Mother Regulations intends to equalise the braking of a train, for example: 50% of pedal force on the tractor = 50% of force on the trailer.

While the intent is to improve safety, the reality is that most agricultural trailer brakes operate at a far lower efficiency than required to generate adequate deacceleration with anything other than extremely heavy braking from the tractor, creating a risk of jackknifing.  

This contrasts with older tractors, where the trailer brakes would be actuated with the brake lights to begin slowing the trailer before the tractor, preventing jackknifing and providing greater braking pressure to the trailer.

At worst we have had customers whose tractor brakes have been worn out in as little as 300 hours and operators genuinely worried about being able to stop when on the road.

Our Solution

With our relay valve kits, the service braking line to the trailer is boosted with an additional 1 Bar of pressure across the working range up to the maximum pressure of 8 Bar. 

This feed is taken from the tractors air reservoir and does not interfere with or detract from the tractors braking in any way. 

With the additional pressure, braking will behave in a similar way to pre 2018 tractors and have received very positive feedback from customers.  

Compatible With All Vehicles

These kits can be fitted to any machine.  The valve itself comes from Wabco to ensure the same quality of parts and instruction manuals as any of our tractor or trailer air brake kits.

Supplied & Fitted or Supplied Only


While we can supply kits to any part of the UK and Ireland, we can also offer a fitting service.

Fitting is typically completed in 1-2 hours and can be carried out at almost any location.

As part of the fitting service we will also test the system operation and should a trailer be available, ensure it is correctly set up for your machinery.

Simply contact us with your tractor details and location for a quote. 


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