Ke25 Master Upgrade - Non Boosted. Help Needed!

[KE25_rolla]

Hey guys,

 

I am in the middle of transplanting a TE27 hydraulic pedal box into my KE25 but need some assistance

with replacement master cylinder options. I am not going for a booster as I prefer the natural feel.

 

The setup in the rolla is as follows.

 

KE25 71 model

TE27 hydraulic pedal box

3TC (to be turbo'd at a later date

Single webber so room is not an issue

ADM AE86 struts and calipers

Standard diff with drums

 

Can someone who has had success with their setup please let me know what the simplest and best option

for a replacement master cylinder.

 

Yes there are a lot of options out there and info on the forum but a lot is heresay as opposed to sucessful

conversions.

 

Your help is appreciated.

 

Cheers

[altezzaclub]

What diameter is your TE27 m'cyl, and what diam is the AE86's??

 

I've found the Toyota cylinders to be fairly interchangeable, and the two parameters you are playing with are both related to diameter- a larger diameter gives a higher pedal but a harder brake pedal. A smaller diameter cylinder will have the pedal going down further but will give you more leverage.

 

The larger rear cyls on the Celcai diff in my KE70 has the pedal going down further, about 40mm down to hard braking but its still 100mm off the floor..

 

The '86 diameter will give you an idea of what the factory needed to work those size calipers, but you might need to be 1/16" inch smaller to get some leverage without a booster.

[KE25_rolla]

Currently the master is the standard KE25 item. I have read that the Ford Meteors and Galant masters will fit.

I think standard bore size of master is 11/16 but will need confirmation if anyone knows?

 

Maybe the idea of the 86 master is the way to go, however will this suit a drum brake rear as the 86's more

than likely came out with disc rear? I am also not sure if the brake proportioning valve needs to be kept or

simply thrown over my shoulder.

 

Brakes are something I have never had to play with so a massive learning curve.

 

Cheers

[altezzaclub]

Keep the brake proportioning valve until you try it all. You may not need it with the bigger front brakes, but you won't know until you try it.

[Redwarf]

http://www.rollaclub.com/board/topic/7663-redwarf-rebuild-v40/page__hl__redwarf__st__45

 

That was my effort. Not much progress from there unfortunately.

[KE25_rolla]

http://www.rollaclub...redwarf__st__45

 

That was my effort. Not much progress from there unfortunately.

 

I did already sus out your post but alas no final outcome as yet!

 

I spoke to a local guy in Brissy today regarding new brake lines. He has quoted around $150 for the fronts

double flared as required. He has also advised to keep the proportioning valve and try the AE86 master.

The said the most important thing is that it is jetted correctly otherwise you end up with severely biased

brakes. He has also suggested another guy who is supposed to be a true legend when it comes to braking

systems locally.

 

I will keep you updated on the progress. Just being cheap and lazy trying to find a tried and tested setup

that works!

[parrot]

AE86 & TE27 are both 13/16. Earlier TE27's were unboosted.

[KE25_rolla]

AE86 & TE27 are both 13/16. Earlier TE27's were unboosted.

 

I'm going to try a KE70 master as apparently these are the same as the '86 masters

 

The TE27 pedal box looks like a bit of work to get in place but nothing major.

[parrot]

ADM AE86's were drum rear. The prop valves do differ between ae86 drum and disc rear. I suspect your main issue would be the rear slave cylinders. If I can find it in my library, I will post up the ae86 rear cylinder bore, unless someone comes up with it beforehand. There are two different bolt patterns for ae86 brake masters, the less common Jap sourced one being diagonal. Whatever, all ae86's were boosted so you will need to work out how to fit these to your pedal box without a booster. I imagine Ke70's were also. Have you looked about on toymods? They love this sort of thing on there.

[KE25_rolla]

Thanks Parrot - One of the guys has a KE70 master so will give it a go to see if it works.

 

Let me know if you have any luck from your library!

[parrot]

S series rear wheel cylinders look to be 13/16. KE2x were available with either 3/4 or 13/16, so you may be alright there.

 

Just suss out whether the booster will fit in position. The TE27 booster is small (7.5 inches?) and the master cylinder is situated very close to the strut tower.

[styler]

Ah yeah it was quite a bit of work the old brake system, last I remember something like...

Theres residual pressure valves for drums, none for disks unless master below caliper height (different psi avaliable)

Something about the prop valves for front to rear bias... these can be external or may be already built into a twin master

The residual pressure valves may be removable in some masters (usually drum circuits) or added externally to a circuit

The twin master engages the fronts partially then rears to avoid lockup

Also consider brake pedal ratios somewhere in there for non boosted, need a huge leg or bigger disc / caliper setup

The caliper bore size to master bore ratio must allow to calipers to engage the pads (1 pot vs 2pot vs 4pot fluid capacities)

 

It can get really tricky, hopes this gets you thinking but definately consult a specialist about everything first.

[KE25_rolla]

Styler - Your scaring me now mate!!

 

I am going to talk to a brake specialist about it to make sure I get it right first time! Don't want the

hassles of chopping and changing setups, brakes failing and locking up etc...

 

Will keep you posted on what does actually work as I can't find a lot of successful installs.