Having just learned to do this myself I would say it's straight-forward once you know how
There are various small things that can trip you up. But Tony has given what I would consider to be the #1 piece of advice. The rod, counter-intuitive that it is, stops fluid leaks while you work.
The next most important advice is not to pump the brake pedal when you are bleeding the brakes. I learnt this off Tony too. Be patient and gravity bleed. Or impatient and buy a pressure bleeder (brilliant £50 investment). The pressure bleeder is also ideal for brake fluid changes which is worth doing at the same time if you are not sure of how old the fluid is and/or the condition. There are a couple of forum members on here at the moment who may have damaged seals from pumping the brake pedal and who can't get the air out now. Pumping brake pedals was fine on 1970s cars (I did it myself) but more modern cars don't like it apparently.
The other advice fresh in my mind is:
- First time around I would buy the brake pipes off the shelf to make life a little easier. My facelift needed 2x 910mm pipes. I bought them from ebay seller bigbadnev. Who turned out to be very nice actually and only charged £6.49 ea. In fact at that price am I ever going to make my own? I sent photos of the fittings to make sure they were made up correctly. If I was ordering again I would probably only get 900mm but it makes little difference as you just lose it in a slightly larger loop before the in-board union
- When you're removing the old pipe it's much better to cut the old pipe at the union and get a proper socket on it (and mole grips on the flexible ferrule). They can be tough to undo
- Be careful removing the brake pipe from the plastic trailing arm clips. They become brittle with age, the closing part of the clip can snap off then you will have to replace it otherwise the clip just becomes a guide
- You don't need a bespoke bending tool. I used the outside of a deep socket matched to the bend radius of the existing pipe. I found the best way to bend the pipe correctly was to put a bend in and then cable tie the section just completed so it couldn't move. It didn't take me long at all and the MOT tester (who in other posts you will see I was otherwise a bit grumpy with) said it was the best amateur job he'd ever seen. I think he was quite new
- The bleed nipples should be carefully prepared to make sure they free off. Again Tony advised me here; clean off the dirt from the nipple, give it a few gentle whacks on the end with a hammer and then tighten it fractionally just enough to feel it move. Again counter-intuitive but it works - just keep the movement fractional. If you shear the nipple head off undoing it you are likely to have to replace the caliper. This little procedure reduces the risk considerably
- The bleed nipples only need a quarter of a turn. Not a half turn. You will let air back in from the nipple thread otherwise. This will be obvious from a stream of fine bubbles after the bigger bubbles have stopped. The nipples don't need much to tighten them. I've seen the force described as 2-fingers (ie not a whole hand)
- The brake unions I also started off with 2-fingers only. And ended up with mole-grips on the flexible hose ferrule and whacking them up quite tight to stop the leaks
- I collected the displaced brake fluid in a jam jar with the lid on and a hole punched through the lid for the bleed tube
- Once you have it back together and have bled the brakes get someone to pump the brake pedal and hold a tissue to the union to check carefully for leaks. Better to discover it on axle stands than on the road...
- Get drip trays under every point you touch, the 4 unions, the bleed nipples and the reservoir. You will end up with fluid on your working surface otherwise.
And if Tony corrects or adds to any of the above listen to him as he is definitely the forum expert
