A weekend brake ……
Prior to me buying the Roadster, it had failed its 2017 MoT test due to a problem with the offside rear calliper, which was replaced. Annoyingly, for my 2018 MoT, the nearside rear calliper caused a test failure. The garage replaced this for me.
For the 2019 MoT, the tester noted that the nearside calliper appeared damp, but it was not a test failure. I told him that I hoped it was not leaking as it was they who replaced the whole unit the previous year.
Prior to the 2020 MoT, we all went into Covid lockdown and my MoT period was extended by 6 months. I decided to replace all discs and pads and, while everything was dismantled, to inspect the nearside rear calliper.
Replacing discs and pads is a job I’d done on other cars. For the Roadster, I’d read a number of guides (including ones from the MX-5OC) and seen the videos, so I did not expect any problems. I should have known better. You have to be a member of the ownwers’ club to see these:
First task – on to the interwebthingy to get some parts:
Rear Brake Pad Set Blue Print ADM54254
Front Brake Pad Set Blue Print ADM54252
Pair of Front Brake Discs Blue Print ADM54348
Pair of Rear Brake Discs Blue Print ADM54328
It soon became apparent that the system would need additional bits - a couple of clips were missing, one of the slider pin boots was damaged and the shims had seen better days. So, back to Ebay for:
Front Pad Fitting Kit Anti-Rattle Clips
Front Brake Caliper Guide Slider Pin Kit
Front discs and pads were first. I removed the carriers to clean them up and file down some corrosion to get the new shims to seat correctly. No significant problems, but the shims would spring off while inserting the pads.
Offside rear next. A bit trickier extracting the disc and again I cleaned up the carrier. The big problem for me was that, worse that at the front, it seemed impossible to keep the shims in place while trying to get the pads inserted. After a number of frustrating failures, I pondered the problem over a mug of tea. I’d tried to hold the shims in place with string and then electrical wire, but it was all too thick. I remembered I had some very fine bare wire I’d kept from my dad’s “may-come-in-useful-one-day” box (it must be hereditary) and figured this wouldn’t interfere with fitting the pads and was thin enough to be easily pulled-out when the pads were seated. It worked.
I saved the nearside rear until last, not knowing what I might find. I discovered the cause of the damp calliper noted at the MoT test. The rubber seal was slightly damaged and had not seated correctly.
I would now need:
Brake Caliper Seal Repair Kit (3207)
Just in case I had to remove the calliper to do the work, I also bought:
Banjo Bolt Copper Crush Sealing Washer
Plus a few tools to make life a little easier:
Laser Tools 6498 Brake Bleeder Wrench 8mm
Laser Tools 6497 Brake Bleeder Wrench 7mm
Laser Tools 6820 Silicon Hose with Valve 1.2m
I did manage to replace the seal with the calliper still connected, but it was awkward and if I ever have to do it again, I’d remove it completely. The difficult part is getting the rubber seal over the piston and seated in both grooves - not easy at my age, hunched over in the wheel arch. There are some Youtube videos that cover the topic. This is quite good:
After re-assembling (again using the wire to hold the shims in place), I remembered I had to adjust the handbrake mechanism on both sides. This turned out to be easy - just tighten to pads rubbing and back-off 1/3rd turn.
Having interfered with the calliper, I had to bleed the brakes. I had plenty of hydraulic fluid, so I also did the clutch which, like the diff oil was likely original. The tools I’d bought made this an easy job. I could have done it alone, but I decided to enlist my wife’s help and see what else she had learnt from Ed China.
Finally, a quick test drive and inspection to make sure everything was OK.
The 2020 MoT test was passed with no issues.