Saga / Iswara Rear Brake Disc Solution

[darahhitam]

Just some drum-disk conversion on an Electric Mustang, I came across on the net.


http://www.pengelly.net/images/rear_disk_brakes.jpg

And on a Corvette (Runs on SRA)

http://www.corvetteuk.com/images/pages/drum_break.jpghttp://www.corvetteuk.com/images/pages/drum_break.jpg

http://www.corvetteuk.com/images/pages/disc_break_1.jpg

Linked from:

1. http://[color=#0000ff]http://www.corvetteuk.com
2. http://www.pengelly.net/electric_vehicles.htm[/color]

 

[darahhitam]

Parking brake and other related matters

Another great article from the web. A short course on braking system, literally.

On why most drum brakes have better handbrake bite and most of our rear disk conversions left us with less grip than before.

Does the Mirage/VR4/ST rear disk comes with complete mechanical drum brake unit mounted inside the rear rotor? Anyone knows?

_____________________________________________________________________

(Linked from: http://www.familycar.com/brakes.htm)

Parking Brakes

​

(QUOTE)
The parking brake (a.k.a. emergency brake) system controls the rear brakes through a series of steel cables that are connected to either a hand lever or a foot pedal. The idea is that the system is fully mechanical and completely bypasses the hydraulic system so that the vehicle can be brought to a stop even if there is a total brake failure.

On drum brakes, the cable pulls on a lever mounted in the rear brake and is directly connected to the brake shoes. this has the effect of bypassing the wheel cylinder and controlling the brakes directly.

Disk brakes on the rear wheels add additional complication for parking brake systems. There are two main designs for adding a mechanical parking brake to rear disk brakes.

The first type uses the existing rear wheel caliper and adds a lever attached to a mechanical corkscrew device inside the caliper piston. When the parking brake cable pulls on the lever, this corkscrew device pushes the piston against the pads, thereby bypassing the hydraulic system, to stop the vehicle. This type of system is primarily used with single piston floating calipers, if the caliper is of the four piston fixed type, then that type of system can't be used.
The other system uses a complete mechanical drum brake unit mounted inside the rear rotor. The brake shoes on this system are connected to a lever that is pulled by the parking brake cable to activate the brakes. The brake "drum" is actually the inside part of the rear brake rotor.
(UNQUOTE)

 

[vestax]

Most japanese rear disc brake sets does not come with the drum's , it uses the cockscrew piston type for the handbrake .

Which is why , if your hand brake aint gripping , you`ll have to service the calipers , IE take out the pistons for resurface , and resurface the housing , change new seals & dust cover , and recalibrate the cockscrew , so that both pistons are balance .

 

[darahhitam]

Thanks vesty for the explanation. Didn't know that most japanese rear disk is not equipped with such item.

Meaning that just by shortering/adjusting the cable won't do the trick, eh?


Mine still works OK for now, but definitely not as grippy as when I used the drums.
Resurface the pistons/housing means machining it?

Or enough by recalibration of the "corkscrew"?

 

[vestax]

It's hard to explain , but if you see the logic tightening the handbrake cable doesnt make any big difference .

The handbrake lever that is connected to the calipers , and the lever connected to the caliper / cockscrew can only turn at a certain degree , lets say 90 degree turn

So if the handbrake cable has been tighten or not if you pull the handbrake the lever still turns at 90 degrees .

Just that when you tighten , u shorten the cable distance , which means its more direct / solid feel , but at the end of the way its still doesnt bite .

Cause by tightening the cable its like making the lever standby at 45 degree , and the other 45 degree comes from pulling up the handbrake , so its logic to get direct feel , as you already shorten the cable travel distance . Hope you get me on this .

So if you shorten the distance , but ur pistons is like a srunk dick hiding inside the skin , it will not bite , u have to calibrate the piston to the middle , and just enough to clip with the rotors when the handbrake is been pulled . Not too much , as the pads needs to have some clearence too , if not jam brakes .

Resurface meaning cleaning the pistons by sand paper if its still usable . If not have to change to a new one . Same goes for your caliper housing , if it has been eaten , u`ll have to change calipers , if not it will leak .

Why japanese rear brake disc doesnt use drums ? cause , like said in the article u posted , only those 4 piston brakes will have the drums , as for the single pistons with floating calipers only will use the cockscrew system .

So how many japanese car's uses 4 pots for the rear's ?. Most of them only run on single piston floating calipers .

Cheers

 

[darahhitam]

Thanks a lot for the lengthy explanation dude.
That's right, shortening will make you FEEL like it's short pull though the actual biting remains the same.

Need to sit down sometimes with you and have a real chat just on this matter.

True enough, we don't see much jap cars (others even!) that use 4 pot for the rear. Most is 2-pot I assume?

Thanks again dude.

 

[darahhitam]

Just to share,

Overheard in another forum a guy mentioned the availability of such break shoe for handbrake purpose in the rear disk of a japanese make.

Supertouring rear disk that is.

That makes it one of the good japanese rear disk system, eh?

Anyone with dismantled ST rear disk photos?

 

[vestax]

You can't justify just like that , its just a handbrake mechanism , both cockcrew or brake shoe mechanism works well and there is notting much to compare about , because , brakes which is not on sliding / floating calipers , can't just use the cockcrew mechanism because it couldn't work .

And for a sliding / floating caliper to use the brake shoe mechanism its makes the cost higher , insted of using 2 pairs of pads for the rear , you`ll have 2 pairs of pads & 2 pair of shoes .

Handbrake mainly is for parking , other then that there is not much use for it . It does not help in the overall braking . So how could that justify , its a good japanese disk brake ?

 

[darahhitam]

You can't justify just like that , its just a handbrake mechanism , both cockcrew or brake shoe mechanism works well and there is notting much to compare about , because , brakes which is not on sliding / floating calipers , can't just use the cockcrew mechanism because it couldn't work .

And for a sliding / floating caliper to use the brake shoe mechanism its makes the cost higher , insted of using 2 pairs of pads for the rear , you`ll have 2 pairs of pads & 2 pair of shoes .

Handbrake mainly is for parking , other then that there is not much use for it . It does not help in the overall braking . So how could that justify , its a good japanese disk brake ?

Err, In my context, for those who seek good handbrake bite while retaining having a disk at the back instead of stock drum.

Lemme retract and rephrase my assumption - this makes it better than Mirage/VR4, in terms of having an extra brake shoe just for handbraking where the other two does not?

Braking power/strength aside.

 

[vestax]

Haha I get where you're going , but lets just face the fact , there is no such thing as extra bite , our cars are not equip with disc brakes , when we do equip them , they are from different car's , that is why , the handbrake problem's come in play , because its not meant for our car's , so it doesn't work 100% .

Like i said if you want the extra bite , calibrate the calipers , it would be good as using drum's . Just that most of us , buy & straight bolt on without even thinking to service the brakes with new repair kits , and recalibrate the handbrake .

Once we have done that , im sure there won't be a real problem . My handbrake works fine after calibrating them . Obviously u need to fork out more money for servicing and stuff , but in the end , its worth it . Do a proper job .

 

[1.3 kissa dude]

ALO vestax.....help me...kat mane bleh dapatkan MUFFLER ori Satria GTI....

 

[darahhitam]

ALO vestax.....help me...kat mane bleh dapatkan MUFFLER ori Satria GTI....

Uiks? Since when this thread becomes SGTi's Muffler selling point? :tongue:

Wrong thread la dude. Wrong thread.

 

[darkbob]

hehe.... wrong thread..

anyways,

Good info bro.. although it is lengthy but it is full of Good info's

I think Perdana is using Disc for braking and drum for parking... but i have not seen a Super Touring Rear Disc yet...

 

[khairulishak]

Hi all,
i oso use mirage disk for my saga. engine 4g61t. very good but handbrake less grip. Now I know why lor.
Good info every1. Tenkiu.

 

[Saga Continue]

very true what vesty said...before this my rear mirage disc brake without proper calibrating for handbrake was utterly useless...u basically can push the car even when the hand brake been pulled...but after getting an advice from our super duper fast car taiko vesty and khoyos in late night at ttdi...i manage to solved the problem....not as grip as using drum but at least now i can park on a slope without having to put a gear to make sure the car stay idle...hehehee

 

[khairulishak]

very true what vesty said...before this my rear mirage disc brake without proper calibrating for handbrake was utterly useless...u basically can push the car even when the hand brake been pulled...but after getting an advice from our super duper fast car taiko vesty and khoyos in late night at ttdi...i manage to solved the problem....not as grip as using drum but at least now i can park on a slope without having to put a gear to make sure the car stay idle...hehehee

how much the shop will charge for the service arr?? normally laa..

 

[khairulishak]

Juz wanna share my rear disk brake photo. from mirage. buy it long time oredi. last time cheap. now very expensive.
http://memimage.cardomain.net/member_images/11/web/683000-683999/683815_143_full.jpg

 

[AndyDemarco]

guys i got a question here.

can a front putra caliper & disc be fitted to an iswara without changing the knuckle?

is the knuckle different?

 

[darkbob]

guys i got a question here.

can a front putra caliper & disc be fitted to an iswara without changing the knuckle?

is the knuckle different?

Bro AndaDemarco,

yes...

you can fit a putra disc and calliper on to an iswara knuckle..

but u need to Bring ur original Iswara knuckles and Putra disc and callipers to machine shop.

there they can do it, i did mine, it cost me around RM 170. for both .. left and right.

 

[AndyDemarco]

thanx mate. anyway the disc is from a gsr so its already pcd 114.3.