brake info for ra28

[bigmat]

just had a new master break cylinder put into my nissan station wagon 80s model and have found the breaking good but not firm like a new car. all other break components are in good working order. the qusteion i am asking that i am doing the pug corona hilux conversion with rear ma70 disks to ra 28 with eg TAKAI post. is this compbo going to feel slightly spongy like my nissan and if so how do i get a harder peddal feel for my ra28 conversion. i want it to feel tight like a new car if possible. thanks.

[bigmat]

can any one help

[The Real Roadrunner]

havnt done it before but ill ask a couple of ppl who have and get back to you.
or put it in the corona/pug/hilux thread.
cheers
linden

ps its brake, ppl might think your havin smoko

[Hash_ra23]

you need a larger master cylinder to use with ur existing brake booster...1 inch master cylinder with the same bolt pattern. Im using one from a ga70 supra as it requires minimal bends to the existing brake lines and bolts straight on. You can also use ones from other a70 supas and also mx83 cressidas and ?? landcruisers and others but they require abit more bending....im pretty sure this was in takais thread too

and again...its bRAKE

[The Witzl]

As per Takai's thread and replies above... MA70, GA70, JZA70, and many hilux brake master cylinders are a direct bolt up, and the *A70 ones require only a minor bend to one brake line.

See here, this is my setup. JZA70 master cylinder on stock RA28 booster... as pictured in Takai's thread.

[tricky]

Yep, big MC is going to firm up the brakes. When you convert to larger calipers, you need to move more fluid to get the same amount of travel in the pistons, hence the sponginess. A larger diameter MC moves more fluid for the same amount of stroke. Be careful though- There is an opinion out there that the 1" master cylinders give a dead pedal feel, and that the 15/16" hilux cylinder is the better option for road driven vehicles.

Another thing which can give some sponginess (but obviously not heaps) is stock rubber brake lines. Converting to ADR approved braided hose gives a poofteenth more response.

[twentyEight]

Actually Karl,

I believe what you have there is a GA or MA70 master cylinder, as you rear brake line outlet is on the outside... (non enigne side)

The JZA70 has the rear brake line outlet on the inside... (engine side)

It's something that Dana discovered and reported on in Takai's thread...

Possibly, JZA70 came out with 2 different types though...

[The Witzl]

that one came off a JZA70 front cut - so i was told.
Quite possible there are two types though.

Another one you can use is a UZS131 master cylinder. 1" bore also

[bigmat]

its brake now.

[bigmat]

so the 1" will give me that rock hard feel im looking for. i trust you on this witz. i do not want a dead pedal.

[The Real Roadrunner]

so the 1" will give me that rock hard feel im looking for. i trust you on this witz. i do not want a dead pedal.

depending on your setup a 1" may be to firm. best off working out piston sizes in calipers from the factory and then figure out the extra % needed with your new calipers and upgrade accordingly.

im not saying anyone is wrong just that your setup may be different to theres.

cheers
linden

[WDE_BDY]

The discussion in this thread -

http://www.toymods.net/forums/showthread.php?t=25587

Seems to lean more towards 15/16", worth a read at least.

Callum

[The Witzl]

the 1" master is quite firm... and yes it can be too firm at times. I've only got stock brakes on my car, but i dont mind a having a stiff pedal.

My booster is in good nick, so it's not too bad for me - but if your booster aint performing at it's best, then it would definitely be too hard. Especially with stock brakes.

A good balance, as Callum suggested, is the Hilux 15/16" master cylinder. They can be bought new very cheaply too. Bigworm can tell you what master cylinder he bought

[bigmat]

cheers for that