TideLog Posts Tagged “replace drivebelt”

I love the Dennis Dart! It is such a quick bus, especially given that at 11.2m long it is only 800cm shorter than a normal city bus. It feels like you’re driving a car, the engine is so quick, and the body so light. Rikku bought her Dart two years ago, it’s a 1996 P reg, I completely overhauled the engine and gearbox, it failed an MOT for the previous operator and they decided to scrap it. It was sat there all sad and lonely in the scrapyard when we went to buy a ZF gearbox for one of our Volvo B7RLE’s, I couldn’t let it get crushed, neither could Rikky, she thought it was cute! It came home to the garage with us, I overhauled it completely, now she’s in regular service as a Bullring Centre shuttle bus!

I raced Rikku’s 1996 P reg Dart against her 2009 59 plate Volvo B7RLE last year, the Dart left the Volvo in the dust! The Volvo B7RLE has a Volvo D7E290 inline 6 cylinder, 318kw Euro 5 engine with ZF 6HP550 6 speed gearbox. The Dart is only a Euro 2 spec 6-cylinder 108kw Cummins with 4 speed Allison gearbox! It has less output power and less gears but still managed to outrace the Volvo! Even when they’re both up to full speed on a runway the Dart stays ahead of the Volvo!

That day was so much fun! Rikku lost a bet, she bet that she’d beat me by driving the Volvo, and I gained £10 as lunch money in the canteen!

The thing I like about the old Dennis Dart is there is none of the modern multiplex computer controlled stuff in it like all Rikku’s modern fleet, there’s just an engine ECU and a transmission ECU for the auto box. There’s none of the new common rail injection either! As much as I love multiplex systems, and common rail electronic injection, it’s nice to go back to the days when it was just you, the engine/gearbox, wheels and road, with no computers controlling the experience, telling the gearbox or engine how to react. Dennis sure know how to name their buses. Since the partnership of Alexander the bus body manufacturer, and Dennis, to make the Alexander Dennis company, the Dart is still around! Yep, the Enviro 200, 300 and 500 still bear big resemblances to the old Dart, in both interior and chassis. The engines are much more up to date, they have all multiplex systems, and the vehicles are a bit heavier, but the old Dart still lives on…

Anyway… One of Rikku’s contacts in the bus industry sent me the Dennis service manual a few days back, which is a godsend, because Rik still uses the Dart on our Bullring route, a lot of elderly people use it and they like the Dart because it is roomy and a very low floor. I’ve had to use pure guesswork servicing it as there are no manuals on the web. So, this is my first article! I’m not allowed to distribute the manual, Dennis will kick my butt! I don’t wanna upset them as I love their customer service and buses, so if you need help, ask and I’ll do an article!

My first article is on changing the drivebelt, as it is a consumable part!

Models Covered: Dennis Dart SLF SPD (Super Low Floor, Super Pointer Dart, with Plaxton Pointer body)

Chassis Models: SFD466BR1*GW3, SFD466BR1*GW4, SFD476BR1*GW4, SFD476BR1B*GW4, SFD476BR1B*GW3, SFD477BR1*GW3, SFD477BR1B*GW3


Visually inspect the belt. Pay close attention to the ridges on the underside of the belt that sit in the grooves of the pulleys.  Check the belt for intersecting cracks.  Transverse cracks (across the belt width) are acceptable.  Longitudinal cracks (direction of belt length) intersecting with transverse cracks are NOT acceptable.

Renew the belt if it is frayed or has pieces of material missing, or damage to the tensile members in the belt, these are crucial for friction. I always like to replace them as soon as they start squealing, but always check the tensioning as this sometimes causes belt slip, not wear. Letting the belt slip can damage it too because the belt gets hot and disintegrates.

1. Check that the master switch is at OFF with the engine stopped. Let the engine cool, as the belt and pulleys of all driven components will be very hot, especially if the belt has been slipping.
2. Using a bar from a socket set, in the square hole in the arm, turn the automatic belt adjuster clockwise to remove belt tension.
3. Holding the adjuster in the raised position, remove the old belt and fit the new one, ensuring that the belt seats correctly in the grooves in the pulleys. A misplaced belt will damage pulley bearings, and the tensile memebers in the belt itself.
4. Lower the adjuster on to the belt and see that the belt is adequately tensioned.

Comments No Comments »