Brakes not so hot when cold !

[mark-ashley]

Has anyone come across their brake pedal being proper stiff in cold weather to the point that the brakes don\'t actually work but then starts working again once the brakes have warmed up ?
 
I read somewhere this was relay fault on the car and should have been resolved by a mazda recall, anyone experience the same thing and if you did, resolved by yourself or a helpful mazda dealer ?

[MaLicE]

i dont have that problem i have ferodo ds2500 pads and they are a bit wooden untill you have heat in them, but then they stop well lol...

[SiH]

What pads are you running?
DS2500\'s (AKA kid killers) need fair heat in them to get going, as do a fair few other pads.

[AtomicRex]

Sounds worse than a DS2500....maybe a DS3000?  Or maybe water in the lines...which has turned to ice? lol  (sorry flippant remark there!)

[NurburgRob]

The latest DS2500s are a new compound and don\'t suffer so much from poor friction when cold.  How old are the pads? where did you get them?

[Red and Single]

doesn\'t sound right to me, get it looked at.

[rxangus]

You mean like this?

http://www.mazdarotaryclub.com/forums/showthread.php?t=3586

Angus

[AtomicRex]

On a practical note I think the first thing you should do is change the fluid.  You aren\'t going to get these problems from the pad, as it sounds more like a hydraulic lock of some respect preventing the piston to travel back again.
 
Check the seals in the master cylinder, but I really doubt the fluid has been changed for a long time so that would be my first call.  We have a second hand master cylinder if you want to try that?

[SiH]

Just to clarify - Are they really hard to push but still work (implies to me a possible issue with vacuum assistance), or is it more that you get normal travel and \'feel\' but not much happens (would guess more pad related, but as above, seems very unlikely unless  you are running super track spec retina detachment pads), or more that the pedal goes to the floor with little or no result (would suggest hydraulic issues - M/C, fluid, or the like -  as above)?

[mark-ashley]

I replaced the clutch line a little while back, maybe 3 months and as far as i am aware the clutch fluid also supplies the brakes, from the same resovoir at least. What i am seeing is the brake pedal is stiff as a board from start up to about the 4th or 5th time it\'s pressed, then everything is back to normal and works like a charm and the issue does not reappear until the car has been left in the cold again. I have recently replaced the pads and disks on the front so deffo not an issue there, it is only when the car is started from cold....

[mark-ashley]

This is the brake recall i am going on about, think it might be what is going on with mine possibly
 
AUG 02, 1996 | Recall ID# 22498

Recall Reason	SERVICE BRAKES, HYDRAULIC:POWER ASSIST:VACUUM:HOSES, LINES/PIPING, AND FITTINGS
Recall Date	AUG 02, 1996
Model Affected	RX7
Potential Units Affected	13900

Recall Summary OIL MIST CONTAINED IN THE ENGINE INTAKE AIR CAN COLLECT OVER TIME IN THE BRAKE VACUUM CHECK VALVE PREVENTING THE CHECK VALVE FROM OPENING AT THE SPECIFIED PRESSURE REDUCING POWER ASSIST TO THE BRAKES.

Consequence BRAKE PERFORMANCE CAN BE DIMINISHED INCREASING THE RISK OF A VEHICLE ACCIDENT.

Remedy DEALERS WILL REPLACE TWO VACUUM HOSES, INCLUDING THE CHECK VALVE, WITH MODIFIED HOSES.

Notes MAZDA (NORTH AMERICA),INC   Unfortunately there doesn\'t seem to be anyway to check if this has been done !!!!

[SiH]

tbh it does sound like it\'s a servo assist problem, so that could well be relevant.

[rxangus]

On my FD the brake pedal is (usually but not always) rock solid if the car has been left overnight but can be made to  return to normal resistance if pushed a few times. I get a small change (increase) in engine revs when the resistance changes. I\'ve had the fluid, pads and discs changed since the problem first started and a complete engine rebuild at WGT too. I asked Pip to have a look but he couldn\'t find anything wrong. It\'s not a cold weather problem  don\'t think - just the car sitting for a while. Usually it\'s okay in the evening if it\'s been left all day. I just live with the issue. Mine\'s a 1996

[mark-ashley]

Mate, that\'s exactly what i am getting, thanks for adding what you have done to your car and the issue still being prevelant, will save me a few quid ! TBH, i\'m happy to live with it, not the end of the world, i was just interested to see if anyone else had this issue and if they managed to resolve, thanks to all for your comments :0)

[rxangus]

I was at WGT last week and showed Pip the Mazda recall notice above. He agreed that it could cause the problem with the solid brake pedal so fitted a new vacuum hose. Only one is needed on RHD cars.

Anyway it seems to have fixed the problem as I have normal brake pedal pressure even after the car has been sitting overnight!

Thanks to mark-ashely for finding the recall.

I\'ll post the required Mazda part number shortly. The hose goes between the servo and the manifold and contains a check valve. Costs £31