RA28 M/C upgrade

[Snyper]

hey guys, just put the corona rt132 struts into my RA28, so now have twin piston front calipers the brakes feel a bit doughy and we seem to have a little more rear brake than front....
what is a relatively easy bolt in master cylinder upgrade if there is a bolt in one, or what do people suggest?

Brendon

[BigWorm]

There's quite a few, the most common/popular seems to be the G/M/JZA70 master cylinder, which is 1". I used a landcruiser MC as it was available brand new, but both of these require the brake lines to be modified to suit (IIRC).
I'm pretty sure MX83 has the brake lines in the same spot, if you can get one of these & get it rebuilt & resleeved that would be my recommendation. Also they're alloy, lightweight & shiney FTW.

[Snyper]

mx83.... cressida?

[TurboRA28]

Be careful going too large.. I went to a 1" MC and the effort on the peddle is too much IMHO. The 15/16th was much better suited.

[Rodger]

I do not believe you have an issue with the RA-28 Master Cylinder sizing wise. It is 15/16inch in size already and should be good for that brake combination. Next size up is 1 inch but finding a four bolt one, I am not sure what off.

I have a similar issue with a 1 inch M/C in my TA-22. A bit soft pedal to start with, rears starting first so is a bit taily and then hardens up to work the fronts really well.

I suspect air in the rear lines and will be checking shortly. It also feels that the rear piston compresses fully to physically contact the front piston within the M/C which to my thinking says there is not enough pressure built up in the rear system to push the front piston.

I will also await anymore help from the forum.

Regards

Rodger

[BigWorm]

I do not believe you have an issue with the RA-28 Master Cylinder sizing wise. It is 15/16inch in size already and should be good for that brake combination. Next size up is 1 inch but finding a four bolt one, I am not sure what off.

I'm pretty sure RA23/28s are actually 13/16".
There are plenty of 4 bolt MCs around, MX73 Cressida is 1", MX83 (yep Cressida) is actually 1 1/16", G/M/JZA70 supra, Lundcruiser etc. A quick look through a PBR catalogue should yield even more, some of which are sure to be 15/16" if that's what you'd prefer. Finding one that doesn't need new lines made up or old lines bent to suit is the harder bit, that's why I recommended the MX83, but now that I realise it's 1 1/16" maybe that's not the best idea.
I'm using a 1" Landcruiser MC (as previously mentioned) and although the pedal is firm, it's something I got used to & actually prefer now. & that's with Corona twin spots on the front & volvo twin spots on the rear.

[The Witzl]

I'm pretty sure RA23/28s are actually 13/16".

You are 111% correct Mr Worm.

There are plenty of 4 bolt MCs around, MX73 Cressida is 1", MX83 (yep Cressida) is actually 1 1/16", G/M/JZA70 supra, Lundcruiser etc. A quick look through a PBR catalogue should yield even more, some of which are sure to be 15/16" if that's what you'd prefer.

Hilux also has the 4 bolt pattern, as does UZS131 crown which is a 1" master.

I just recently fitted a JZA70 1" master cylinder, which was a piece of piss to fit with some relatively minor bending to one of the brake lines on the driver side.

here's a pretty picture!

[Gleno28]

I found the Hilux 15/16th one pretty bloody good too, nice feel, easy fit.

[TA-022]

ive got the ma/ga70 one in my project shell.

4 bolt 1" bore and 1 line required minor 'persuasion' which was slighty hand bent to solve.

cant attest to the feel yet as it hasnt run yet but its the one in the guides every1 raves about needing so it cant be that bad?

[TurboRA28]

I think its a personal preference mate.

IMHO I don't like it and when I get the energy i'll take it off and go back to the Hilux 15/16ths.