Brake work on the Maverick continues, but all is not well. After the horrors of finding one front brake pad worn down to the metal, the overhaul has revealed further issues.
The first step was to pull apart the offside brake – the one with the faulty caliper. During this work, it quickly became apparent that the slide pins that the caliper moves on were totally seized up. This is what caused extreme wear on one pad – the seized caliper pistons just exaggerated the problem. The advice on the Nissan 4×4 Owners Club forum was to remove the entire caliper assembly, so it can be worked on away from the vehicle. If I had a big vice, this would have worked nicely, but I only have a battered Black & Decker workmate, which wouldn’t really help.
The caliper itself is a unit that holds the pads. There are two caliper pots on one side which act directly on one brake pad. The pressure then pulls the whole caliper towards the inside of the car, which thereby acts upon the opposite brake pad. Presumably this is an economic measure as most 4x4s would have four caliper pots per front brake, rather than the two used here. I consider it a fairly flakey idea as it just allows something else to go wrong – the sliders in this case which prevented the caliper from moving correctly.
So, the caliper was quickly lifted out of the way. The next challenge was to remove the slider pins from the caliper carrier. Brute force was necessary, all the while bearing in mind that there’s a good chance of snapping the pins if you get carried away. The pins have a 17mm nut at the end, which initially made me think they had to be unscrewed. No. This is merely to allow you tighten up the 13mm headed bolts that hold the caliper to the carrier.
I used a lot of penetrating oil, and one pin responded well to a chisel and a hammer – eventually coming free. The top one was very, very stuck though. I tried waggling it back and forth with a spanner, then tried the chisel and hammer approach, all the while soaking it in penetrating oil. After a very lengthy battle, it finally came out. No wonder the caliper wasn’t working! On the passenger side, the pins moved beautifully under no more than light finger pressure.
Then I could remove the caliper carrier and then the hub and brake disc. This isn’t too tricky, though there are lots of bits to keep an eye on and remember where they live. The auto-locking hub has to come off (an ideal opportunity to lubricate), then a circlip and some washers, followed by the outer wheel bearing and finally the disc/hub.
Separating the disc and hub proved very tricky, on both sides. For a start, the 14mm headed bolts were a pain to undo. If I’d remembered the instructions I’d seen online, I would have undone these bolts while the brakes were still fitted. As it was, I had to use a bar to prevent the hub from turning. Then the hub and disc seemed almost welded together with rust and friction. It took another serious bout of hammer-and-chisel work to separate the two parts.
Then it was quite easy to fit the hubs to the new discs and re-assemble. A good opportunity to repack the bearings with grease.
Sadly, I ran into problems locating new sliding pins, so work drew to a halt. I thought I’d try reassembling the nearside caliper, but then realised that the pistons were seized here too! Annoyingly, I’d already ordered a new caliper for the offside, so missed an opportunity to combine postage. The calipers cost £67 each delivered. I did consider rebuilding the calipers, but I’ve done it before and it’s not much fun. The parts were proving almost as expensive as a remanufactured caliper anyway, so the bullet was bitten. That means that total expenditure is now past my original £800 desire. I am left hoping that future months will be much cheaper!
And that’s where the project remains for the moment. I’m awaiting parts and just to make life even more interesting, I strained my back badly while clearing up. I hope to recover in time to get the brakes completed this week…