Not convinced about my brakes?

[Martiny]

5.1 is Dot5.....

Sorry?

What does this mean?

[TonyC]

Jon, have you got dot 5 and dot 5.1 mixed up?
Dot 5 is the silicone stuff and as you say horribly hydroscopic. Dot 5.1 can be mixed with dot 4, 3 and other fluids. Although as you say a good quality do4 can have better heat control properties than an average 5.1

If a pedal is very spongy as described but has new fluid and has beenb bled I still think it sounds like master cylinder seals allowing fluid to flow back when the pedla is pushed - it will give just that sort of sensation on the pedal - In fact, if you keep your foot on th epedal hard does it slow sink down to the floor - if it does than the problem is the master cylinder.

[AtomicRex]

Tony

I thought that 5.1 was dot 5???  Or is it a "semi synthetic" type of fluid, which as you say can be mixed???  (I\'m still learning )

Id still stick to the ones I suggested up above.....and for the cost of it get some new seals on the master cylinder, cheaper than repairing the front of the car having gone into a wall!

[TonyC]

ah, common mistake. 5.0 can\'t be mixed with any other fluid. 5.1 can be mixed with the other lower numbers. The products you mention are top notch as you say.

[AtomicRex]

shalln\'t make the same mistake again!

Thank you oh racing guru! :p

[allstaruk]

Ok I\'m going to change the fluid and bleed everything tomorrow then I\'ll let you guys know how its going but i suspect it being a crap master cylinder.

So what fluid should I be using(make and model please) and better still somwhere I can get it?

A

[Grizzly]

Make sure all your Caliper Pistons move smoothly.

Also have a real good look at the Rear calipers, Not sure if there the same as T2\'s but i went through a stage where mates where asking why there brakes Where Poor and after lots of messing it was the handbrake seal in the rear Calipers that was causing air to be drawn in, i only noticed becouse i pulled the Rubber Cover off the back to grease one up and it was full of Fluid.

[AtomicRex]

If you phone Martin at Tweeks 01978 663 014 and ask for either

AP551 £4.52 per 500ml bottle
AP600 £11.66 per 500ml bottle

The AP551 will do fine, but depends on how you drive...if you use the brakes a lot down twisty roads and if you can spare the extra cash so soon after christmas then go for the AP600

Without wishing to teach grandmas to suck eggs....when you bleed the brakes make sure you start with the caliper furthest away from the master cylinder and work you way towards the one that is closest.

To save time on refurbishing the master cylinder I know either Carl or Gary have second hand ones!  Could be worthwhile swapping it over....nothing worse than wasting the nice new brake fluid.

[RAW]

this is all interesting, and useful stuff, as i need to change my fluid asap after boiling it on track. how much do you need in total to do the change?
 
thanks for all the info guys!

[Mazdarotaryparts]

this is all interesting, and useful stuff, as i need to change my fluid asap after boiling it on track. how much do you need in total to do the change?
 
thanks for all the info guys!

Two bottles will be all you need, we have sold  DOT 5.1 Lockheed ( AP )
non silicon fluid for the last few years for FD\'s at £5.63 + vat per bottle

http://www.mazdarotaryclub.com/forums/showthread.php?t=24058

hope this helps

[RemarkLima]

once the brakes are actually working I can still (with a bit of force) get the peddle to touch the floor.

If you can get the brake pedal to touch the floor then either you have a lot of air in the system (need a bleed!) or your MC is fubar\'d.

Probably air in the system but if it\'s this bad it really is dangerous!!! I think the brakes on the FD are pretty good TBH, not much servo assit which is nice.

An easy way to check the MC is lightly press the brake pedal with the engine running, and just keep the same light pressure, if the pedal keeps sinking down slowly then the seal on the MC is letting fluid past so needs an overhaul.

GL!!!

[allstaruk]

Cheers lads will have a look today.

A

[Ricco_04]

If the cap that goes on the MC is split, this would cause problems too?

[allstaruk]

Thinking about it mine\'s seen better days, can anyone confirm this?

[RAW]

confused about whether to get 4 or 5.1 now! i was going to buy 5.1 here:
 
http://www.tokyo-express.co.uk/engine/fluids.php
 
although Clive\'s prices seem good.
 
can anyone clear this up? i use my car for hard road driving but also track work. my standard stuff boiled after a 20min session.:3gears-lh