We’re talking DIY brakes. Why? Because big caravans need better tow-vehicle brakes. Here’s how to upgrade your brakes with a day on the tools for safer towing.
Make no mistake about it, the things we ask our tow-tugs to do are far beyond the imagination of the engineers who design them. Sure, on paper, the vehicles themselves can handle 3500kg on the tow ball, but there’s no such thing as a free lunch. With a caravan on the back, your pride and joy won’t stop or go anywhere near as good as it does unladen. And stopping? Forget about it.
In an ideal world, the camper or caravan brakes will be taking care of the load back there while your tow-tug is just worrying about itself, but things aren’t always perfect. Long descents, emergency braking situations, or even just a brake controller a couple of notches too tame can all mean that your tow-tug brakes are carrying more than their fair share. Something you won’t notice until they’re red hot halfway down a long grade.
The project – an old 80 Series ‘Cruiser
We recently acquired an old 80 Series ‘Cruiser with plans of long weekends at the boat ramp and longer weekends in the bush with a camper and it became glaringly obvious the factory brakes weren’t up to scratch – along with the factory engine, transmission, seats, and suspension – but we digress. So we figured before we wind the jockey wheel down on the tow-ball, we should set about rectifying that.
We looked at a few different options for more stopping power but ultimately decided the Ultimate 4WD Brake Upgrade Kit from Bendix would be the best bang for buck for this DIY brakes project. Coming in a complete kit, it’d have everything we needed from rotors and pads through to brake lines and fluid. The case converting into an esky afterwards was hard to argue with too. Here’s how we did it.
Step 1. Ensure you’ve got everything – including the skills
On the DIY scale of 1-10 for difficulty, a brake replacement is somewhere around the 6 or 7 range for a few good reasons. The actual process is rather simple. The components are typically like for like, so if you’re handy on the spanner roll and are confident you could change some shocks, you can probably change your brakes. If you’re not confident, best leave it to the professionals.
It’s worth mentioning though, that your tow-tug will be properly out of action once you begin. There’s no ducking down to the parts store to get fluid if you realise you ran short. You can piece together a kit yourself, but we found the Bendix offering made life simple knowing it was all in there.
Step 2. Work out what you’re doing
Whether you’ve got a 300 Series or an 80 Series, things like brake lines, pads, and fluid are all going to be reasonably similar to swap over on a DIY brake upgrade. However, there can be subtle differences that may catch you out. On our ‘Cruiser, the rotor itself is installed on the back of the hub. As a result, we needed to completely strip down the wheel hubs, bearings and all, to be able to change the rotor. Other rotors are simply held on by the wheel. It’s important to know exactly what you need to do beforehand so you can have the right tools and parts on hand before you get halfway through the job.
Step 3. Install the rotors
With the hubs stripped down, we were able to remove the bolts holding the old rotor on, bash it off, install the new rotors on and cinch them down. This is a good time to break out a can of brake cleaner (included in the kit) and give everything a thorough clean. Get rid of any built up rust flakes, grease, or general road grime.
There are schools of thought with everything from grease to Loctite for the rotor bolts, but we’ve always found luck with a dab of anti-seize and torquing to spec. You can see the Bendix discs are vented like stock, but also include dimpling and cross-slotting. This not only lets the disc shed off heat more efficiently but also removes brake dust and gases from the surface of the pad. That’s a fancy way of saying your tow-tug will stop better for longer.
Step 4. Get to work on the calipers
There’s a whole lot of science when it comes to brake pad composition, the manufacturer trying to find the balance between noise, wear, outright braking performance and performance under load, at high heat, low temperatures, and not mincing the rotors in the process. All things that are important in bringing your tow-tug and ‘van to a smooth controlled stop over and over again.
The Ultimate pads ticked all those boxes, and came in the kit, so that was a bit of a no brainer for a DIY brake upgrade and install. The pads are pushed in by pistons on both sides. As the pad material wears away, the pistons get closer and closer together, and the new pads simply won’t fit. We gave the calipers a scrub to get years of grime off them, used a piston separator to make a little space, and inspected the rubber boots on the pistons while we were there.
Step 5. Start putting things back together
With the old components well and truly in the bin, it’s time to start re-assembling things and looking for the light at the end of the tunnel. With the pistons still spread wide open, re-install the brake calipers, ensuring the bleed nipple is up the top. A dab of anti-seize here on the mounting bolts will make this an easier job next time and ensure you can get the bolts torqued to spec as well. But keep it away from all the brake hardware.
There’ll be a little brake lube in the box you can put on the slide pins to keep them moving. Give the rotors a once over with the included wipes to remove any contaminants that have found their way in, then pop the pads in, any locking hardware, and move on to the next step.
Step 6. Install the new lines
From factory, your tow-tug would have come with flexible rubber brake lines connecting the hard lines on your chassis/diffs to the calipers. Over time, and with exposure to harsh conditions, these can dry out, crack, and start perishing. While ultimately, they can fail and leave you brakeless, they can also cause issues well before that too.
When you apply your foot to the brake, some amount of force is absorbed by the lines physically swelling. The braided brake lines in the kit are not only 30 years younger than what we’re swapping out, but won’t have that swell either, meaning more force applied to the brakes themselves and a better pedal feel. Swapping the brake lines in is a simple DIY process. A brake line spanner and a pair of pliers are all you’ll need to remove the old units and install the new ones.
Step 7. Bleed the brakes
The kit we got from Bendix came complete with a few bottles of their brake fluid, but you’ll need to pick up some clear tube and a set of brake line spanners as well. With a spanner on the bleed nipple and the tube slipped on the end, get your partner-in-crime to sit behind the tiller and pump the brake pedal 5-6 times, then hold it flat. Crack the bleed nipple, and a combination of air/gunk/old fluid will come sputtering out. When it stops, lock the bleed nipple off again and repeat the process until it’s nothing but fresh, clear fluid coming through with no air bubbles. You’ll need to start at the point furthest from the brake master cylinder and work your way closer, ensuring you keep topping up the master cylinder with fresh fluid as you go. If it runs out, you’ll have to start the process again.
Step 8. Enjoy the fruits of your labour
If you’ve made it this far without calling in a mechanic, congratulations. A brake upgrade is something that every single tow-vehicle will benefit from. Whether it’s the immediately improved bite when you push the stop pedal, or the better ability to fight off heat and the subsequent brake fade you’ll get on long steep descents, your towing will be better off for it. All that’s left is to bed in the brakes. There’s multiple schools of thought on how to do it but we reckon hitching up the camper or caravan and heading bush might just be the perfect two-for-one.
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