I’m looking for technical help or recommendations on: Brakes and bleeding process
Hello my fellow MX5-VERS.
My drive home from visiting my parents in Suffolk was eventful. I started getting the feeling of driving of small bumps on the road with the steering wheel pulling to the left every so often. So stopped to check the tyres to find my front passenger side brakes quite hot.
I waited for them to cool down and carried on and it did it again and I stopped and waited. That was the pattern all the way home. What should have been a 2.5 hour trip took over 4 hours.
So, I checked the forum as usual and ordered the new pistons, seal and for good measure, new stainless steel braided brake hoses for the front.
I spent the last weekend replacing the pistons and seals. The passenger side piston was totally stuck inside the caliper and took me a long time to get it out.
I asked my daughter to give me a hand bleeding the brakes the traditional way with her pumping the pedal, while I sat by the bleed nipple to let the air out. I started with the passenger side first as it was furthest from the master cylinder.
Got a lot of air out and used over half a litre of brake fluid in the process.
But the pedal still goes almost to the floor when I press it and had to pump it a couple of times to make the brakes work.
I checked the forum again and bought the Gunson Eezybleed kit and tried to bleed the brakes again yesterday. Got more air out in tiny bubbles.
The brakes are still spongy and I have to pump a few times to make them work. Something is not right and I am at a loss.
Are the front brakes linked to the rear?
Do I have to bleed the whole system?
Please let me know if I’m doing something wrong or there is a particular way that needs to be done.
I rebuilt my front calipers recently. One in October and the other in December. In October I used compressed air to remove the piston as I had taken the caliper completely off the car. In December I left the brake hose connected with the caliper off its mounting bracket and used the brake pedal to push the piston out. This is much more satisfactory. I used a hose clamp to reduce the loss of fluid after undoing the hose connections.
After replacing the pistons and seals I pressed the pistons full home and let gravity fill the calipers with fluid. I kept a close look at the level in the master cylinder and not much fluid was used. I found that I only had to bleed the rebuilt caliper to get a firm pedal as air was only in the caliper and not the brake pipes. I used a vacuum pump to bleed the brake and did this single handed.
I wonder whether you lost so much fluid that the ABS pump had air in it. It is correct that with a completely empty system one starts from the brake furthest from the master cylinder but experience has taught me that with care one only has to bleed the specific caliper.
I’ve done lots of brake replacements on many different cars in my time and the two mem method has always got the air out without this issue.
How do I check if the ABS has air in it?
I will bleed all four brakes first and then see if the problem is still there.
The MK3 is a pain, a pressure bleeder is the only way I have found, get one like the Gunson Easy bleeder. You will probably need to bleed the clutch as well if the level was low, as work off same reservoir.
I used a pressure bleeding system as I don’t have a spare pair of feet to do it the trad way.
Worked fine, although the space saver wheel I used needed pumping up twice for the four calipers.
Interestingly, the two rear callipers required a bit of plumbers tape to get the bleed nipples to not draw in external air( these were factory callipers)
I’m not sure if this is even possible or not, but looking at your photo, have you put the calipers back on the correct side? From memory, the brake hose should be at the bottom and the bleed nipple at the top.
Edit… And the Mazda text is upside down and is that an “L” I can see cast into the caliper on the right hand side? In all my years, I’ve never struggled to bleed brakes on an MX-5 using the traditional tube in a jar method.
I was surprised to need plumbers tape but it worked. I recall bleeding the brake line and just getting bubbles despite having obviously replaced what was the whole lines worth of fluid. It freaked me out at the time but having plumbed a couple houses I had a fair bit of tape and memories of when a few wraps was the difference between a leak and not.
Thank you everyone.
I made the mistake of taking both calipers off and replaced the seals and pistons at the same time. I should have done it one at a time. Live and learn.
Thank you everyone for your input. I started the bleeding process from the rear passenger side and worked my way round to the front driver side. As I had the wheels off I replaced the rear brake hoses and cleaned a d painted the disc and calipers.
All back together and working beautifully.
Eezybleed kit - brilliant. Totally recommend it.
Only thing to watch out for is the small clear hose that goes from the pressure bottle to the master cylinder. It comes out quite easily if not fitted properly. Had a little incident that had me swearing profanities when it came off under pressure.
Oh I realised that now after a small incident of getting sprayed with brake fluid in my face. Lucky I was wearing my goggles. I fixed the issue by refitting the hose properly (as it should have been from the factory) and then did all the brakes without any further problems.
