What's wrong with my brakes???

Wheels, Suspension, Brakes & Tyres questions and answers

Moderators: timk, Stu, zombie, Andrew, -alex, miata

User avatar
Mr nanotech
Racing Driver
Posts: 1487
Joined: Sat Jan 23, 2010 4:35 pm
Vehicle: NA6
Location: Rotting away in the 'Greater' City of Geelong...
Contact:

What's wrong with my brakes???

Postby Mr nanotech » Tue Sep 27, 2011 5:25 pm

Replaced brake fluid and bled all four corners, adjusted my faulty driver side handbrake. Woot, somehow my brakes are worse than ever.... No air in the lines, pads, calipers and discs haven't changed since, brand new fluid... Yet somehow the pedal feels loose and I have about 50-60% LESS stopping power... WTF

The original plan was to replace with new fluid and get rid of the air in the rear lines. Bled the brakes, no more air in the lines and has nice new clean fluid in it now. I adjusted the manual handbrake thing on the rear driver side as that corner seemed to do nothing with the handbrake engaged.
Everthing should have been working perfectly but it seems the only thing that's improved is the handbrake (which now works fine).

The pedal now feels slacker than before and the brakes don't fully engage until it's completely depressed. Even then, stopping power is average-poor. On top of this, the fronts lock up upon quick braking.

It's really concerning me now because the only thing that's changed since was the fluid. I'm going to do another bleed tomorrow just in case to make sure there is no more air in the lines. I looked for leaks but I can't seem to find any brake fluid stains, so I'm guessing it's not a leak. I'm not sure what else to say.

The brake fluid I used was Castrol DOT4 fluid that comes in 500ml red bottles. I bought 3 of these to be on the safe side (1500ml) but only ended up using about bottle and a half (750ml).

If ANYONE knows what's wrong or has any ideas, I need to know asap as this is my daily driver and I'd like to be able to stop!!!!!!!!!!
Okibi wrote:Abusing Police because of a few corrupt or power hungry idiots is like calling all car enthusiasts hoons. :roll:

User avatar
Cerberus
Driver
Posts: 43
Joined: Sun Nov 28, 2010 2:17 pm
Vehicle: NA6
Location: Brisbane

Re: What's wrong with my brakes???

Postby Cerberus » Tue Sep 27, 2011 5:45 pm

Brake booster not working properly?
I remember I had a Nissan exa where it was stuffed and the brakes would be nothing until fully depressed and then it would still just be like pushing my foot against a wall for barely anything.

Before staring the car try pumping the pedal 5 or so times to build up pressure, then keep the pedal depressed as you start and you should feel the pedal go down a bit.

If I recall correctly this is how to check whether the booster is functional but I'm sure somebody knows better than me.

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: What's wrong with my brakes???

Postby NitroDann » Tue Sep 27, 2011 6:13 pm

That an effective test for the booster, but I reckon theres air in the lines.

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

User avatar
Mr nanotech
Racing Driver
Posts: 1487
Joined: Sat Jan 23, 2010 4:35 pm
Vehicle: NA6
Location: Rotting away in the 'Greater' City of Geelong...
Contact:

Re: What's wrong with my brakes???

Postby Mr nanotech » Tue Sep 27, 2011 6:26 pm

Yeah i've been thinking this over and over and I have a feeling that there is still air in the lines and may have been sucked back in when doing up the bleeder valves. Since I'm working with my 70 year old father, there may have been a miscommunication between us regarding foot on and off the brakes. I'm going to bleed it again tomorrow morning and see how I go before I do anything rash. This should solve the problem i think.


EDIT!!!!

Cerberus, I tried your test but it ultimately went nowhere as the pedal touches the backwall anyway lol. Like I said, I'll bleed in the morning and see what happens.
Okibi wrote:Abusing Police because of a few corrupt or power hungry idiots is like calling all car enthusiasts hoons. :roll:

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: What's wrong with my brakes???

Postby NitroDann » Tue Sep 27, 2011 6:51 pm

Bleeding should be a one person job.

Just open the valves, all 4. And then close them when the fluid runs clean. No air can possibly get in.

And it only takes 10 minutes.

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

User avatar
Mr nanotech
Racing Driver
Posts: 1487
Joined: Sat Jan 23, 2010 4:35 pm
Vehicle: NA6
Location: Rotting away in the 'Greater' City of Geelong...
Contact:

Re: What's wrong with my brakes???

Postby Mr nanotech » Tue Sep 27, 2011 6:54 pm

I don't have car stands
Okibi wrote:Abusing Police because of a few corrupt or power hungry idiots is like calling all car enthusiasts hoons. :roll:

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: What's wrong with my brakes???

Postby NitroDann » Tue Sep 27, 2011 7:10 pm

Either do I. I use 8 spare wheels.

Just do 1 end or side at a time if you just want to use a jack.

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

User avatar
tobias
Fast Driver
Posts: 300
Joined: Wed Jul 06, 2011 10:10 pm
Vehicle: NA6
Location: melbourne

Re: What's wrong with my brakes???

Postby tobias » Tue Sep 27, 2011 7:32 pm

nanotech wrote:Yeah i've been thinking this over and over and I have a feeling that there is still air in the lines and may have been sucked back in when doing up the bleeder valves. Since I'm working with my 70 year old father, there may have been a miscommunication between us regarding foot on and off the brakes. I'm going to bleed it again tomorrow morning and see how I go before I do anything rash. This should solve the problem i think.


EDIT!!!!

Cerberus, I tried your test but it ultimately went nowhere as the pedal touches the backwall anyway lol. Like I said, I'll bleed in the morning and see what happens.


That's a bad way to bleed brakes. Since your pushing the pedal where it has never been before the seal on the master can get damaged. Best way as Dan said is to open all the nipples stand back and watch don't touch the pedal, good luck, just make sure the fluid never goes empty or your going to have to start over.

User avatar
gslender
Speed Racer
Posts: 2330
Joined: Sat Feb 19, 2011 10:49 pm
Vehicle: NA6
Location: Brisbane, QLD

What's wrong with my brakes???

Postby gslender » Tue Sep 27, 2011 9:41 pm

orangemx5 wrote:
That's a bad way to bleed brakes. Since your pushing the pedal where it has never been before the seal on the master can get damaged. Best way as Dan said is to open all the nipples stand back and watch don't touch the pedal, good luck, just make sure the fluid never goes empty or your going to have to start over.


Wonder why they sell brake bleeding kits then?
MX5 91 NA6 LE completely stock and loving it!
MX5 92 NA8/ITBs Silver "aka Track Beeotch"

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: What's wrong with my brakes???

Postby NitroDann » Tue Sep 27, 2011 9:47 pm

The same reason anyone sells anything, because people will buy it and profit is to be made.

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

User avatar
Charlie Brown
Speed Racer
Posts: 2623
Joined: Mon Apr 28, 2003 11:00 am
Vehicle: NC
Location: Sydney, Just out of Dragon Territory over the bridge in the "Shire"
Contact:

Re: What's wrong with my brakes???

Postby Charlie Brown » Tue Sep 27, 2011 10:16 pm

Did you have your ignition turned on? You need to have the solenoid on the booster open to bled the system properly.
Image

Wakefield 1:09.13 Eastern Creek GP 1:50.198 Ext 2:17.538 Sth 1:02.9003
Phillip Is 1:58.50 Winton Short 1:10.7 Lakeside 1:05.7711 MDTC 45.20

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: What's wrong with my brakes???

Postby NitroDann » Tue Sep 27, 2011 10:25 pm

LOL, That was a troll post right?

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

User avatar
Charlie Brown
Speed Racer
Posts: 2623
Joined: Mon Apr 28, 2003 11:00 am
Vehicle: NC
Location: Sydney, Just out of Dragon Territory over the bridge in the "Shire"
Contact:

Re: What's wrong with my brakes???

Postby Charlie Brown » Tue Sep 27, 2011 11:36 pm

 Post subject: Brake Pedal going to the floor...Posted: 24 Feb 2009 11:44 am 

Racing Driver

Should have said ABS not booster, but then you might not have ABS.

Taken from another post from CT.....

Make sure you bleed with the ignition turned on and the sequence from longest lines to shortest lines for ABS cars. It is also highly possible that your technique for opening and closing the bleeders is letting air back in. If you use the Elf HTX fluid and the car is properly bled, you should not be having this problem.

_________________
<---Nemo is now.
2009 MX5 Class 2B National Champion
Image

Wakefield 1:09.13 Eastern Creek GP 1:50.198 Ext 2:17.538 Sth 1:02.9003
Phillip Is 1:58.50 Winton Short 1:10.7 Lakeside 1:05.7711 MDTC 45.20

User avatar
Mr nanotech
Racing Driver
Posts: 1487
Joined: Sat Jan 23, 2010 4:35 pm
Vehicle: NA6
Location: Rotting away in the 'Greater' City of Geelong...
Contact:

Re: What's wrong with my brakes???

Postby Mr nanotech » Tue Sep 27, 2011 11:45 pm

Charlie Brown wrote: It is also highly possible that your technique for opening and closing the bleeders is letting air back in


Pretty sure this is the reason lol. I'll give it another stab tomorrow. It's a 1990 na6 so I really don't think ABS is an issue here :lol:

Give me a break Dann!! This is the first time I've replaced the brake fluid
Okibi wrote:Abusing Police because of a few corrupt or power hungry idiots is like calling all car enthusiasts hoons. :roll:

User avatar
tobias
Fast Driver
Posts: 300
Joined: Wed Jul 06, 2011 10:10 pm
Vehicle: NA6
Location: melbourne

Re: What's wrong with my brakes???

Postby tobias » Tue Sep 27, 2011 11:59 pm

Like I said. Open all the nipples, go have a cup of tea (or a beer) come back close nipples, half pump the pedal until hard and bam you have a brake pedal


Return to “MX5 Wheels, Suspension, Brakes & Tyres”

Who is online

Users browsing this forum: No registered users and 151 guests