TA22 master cylinder with 1 inch bore?

[sillycar chick]

If theres an issue with pedal pressure, maybe they need a bigger booster? The 22s have such a small booster.

RA28 boosters are bigger than the TA22s. My guy has a 1" supra MC on his RA28, and pedal pressure is pretty good. I cant notice any sponginess and its not hard on the leg either. Only problem is 1" supra MC doesnt bolt onto a TA22 booster, and RA28 booster doesnt bolt into a TA22, theyre different spacings on the firewall Sucks cos I already looked into that.

Has anyone come across a bigger booster that bolts straight into the TA22, and has a 1" MC available that will bolt straight onto the booster? Something Ive been meaning to look into but havent had the time to be hunting around wreckers lately Would probably need to find something that doesnt foul on the clutch MC either

[Rodger]

Guys and girls it is not about the size of the booster as such.

As the bore has increased to one inch from 3/4? or 13/16? (cannot recall exactly the TA and RA sizes), and the caliper bore (size) has not nescessarily changed then it changes the pressure ratios.

An increase in the bore of a M/C for a given caliper size decreases the stroke and an increase in the pedal pressure is needed for the same braking force on the rotor.

My pedal feel is a bit heavier (not a lot) than the original. It comes about, for me due to the increase in the caliper size to a TN Maga one I use.

A one inch bore M/C pushing into a TA-22 or RA-23/28/40 caliper would be very heavy, but put on those favoured Hilux calipers and it should be a nice pedal feel as the caliper size has gone up markedly.

People would find if they combine the Camry caliper and the Camry M/C with the TA-22 booster the pedal pressure would match that of the original donor car. Apart from how the factory sets how the vacuum is applied to the booster and pedal adjustment/ratio in the Camry and then add to that the brake pad material.

Regards

Rodger

[TA22 1MZ]

Guys and girls it is not about the size of the booster as such.

As the bore has increased to one inch from 3/4? or 13/16? (cannot recall exactly the TA and RA sizes), and the caliper bore (size) has not nescessarily changed then it changes the pressure ratios.

An increase in the bore of a M/C for a given caliper size decreases the stroke and an increase in the pedal pressure is needed for the same braking force on the rotor.

My pedal feel is a bit heavier (not a lot) than the original. It comes about, for me due to the increase in the caliper size to a TN Maga one I use.

A one inch bore M/C pushing into a TA-22 or RA-23/28/40 caliper would be very heavy, but put on those favoured Hilux calipers and it should be a nice pedal feel as the caliper size has gone up markedly.

People would find if they combine the Camry caliper and the Camry M/C with the TA-22 booster the pedal pressure would match that of the original donor car. Apart from how the factory sets how the vacuum is applied to the booster and pedal adjustment/ratio in the Camry and then add to that the brake pad material.

Regards

Rodger

Rodger,
I use RX7 4spots up front and sprinter calipers at the rear and still have the hard pedal feel. The other person I was referring to before also has a similar upgrade in caliper sizes and when using the 1"M/C also experiences the rock hard pedal feel.
Surely there is an explanation for it and as such a resolution. I havent had time to go into it though, and didnt mind the thought of pumping up my quads and calves in the process Unfortunately, I will end up walking lopsided though with a massif right leg and tiny left leg
Thanks
Jack

[TA22 GT]

Thanks for the replies. It's a bit more scientific than I expected. I need to think about this a bit more, visit the wreckers etc before I know the best combination for my set up which is currently IDB front brakes, T18 dual circuit M/C and rear supra discs with single spot calipers....

Cheers,
Simon

[YLD-16L]

Guys and girls it is not about the size of the booster as such.

As the bore has increased to one inch from 3/4? or 13/16? (cannot recall exactly the TA and RA sizes), and the caliper bore (size) has not nescessarily changed then it changes the pressure ratios.

An increase in the bore of a M/C for a given caliper size decreases the stroke and an increase in the pedal pressure is needed for the same braking force on the rotor.

My pedal feel is a bit heavier (not a lot) than the original. It comes about, for me due to the increase in the caliper size to a TN Maga one I use.

A one inch bore M/C pushing into a TA-22 or RA-23/28/40 caliper would be very heavy, but put on those favoured Hilux calipers and it should be a nice pedal feel as the caliper size has gone up markedly.

People would find if they combine the Camry caliper and the Camry M/C with the TA-22 booster the pedal pressure would match that of the original donor car. Apart from how the factory sets how the vacuum is applied to the booster and pedal adjustment/ratio in the Camry and then add to that the brake pad material.

Regards

Rodger

Most of the people in this thread are across what you have explained (I think), most have upgraded to a 4 pot front caliper too, hence the want of a master cylinder with a larger bore.

What most people are wondering though is why the donor car they got their calipers from had good pedal feel and a lighter application when they have used the same size master cylinder as the donor car had. 95% of that difference in pedal feel comes down to the difference in the size of the booster and the assistance it provides.

I think what has popped up a few times on this forum now is people saying I have fitted X master cylinder and Y calipers to my old car with a small standard booster and my pedal is so much harder to push than it was in the donor car. Simple answer is the vacuum assitance offered by a booster with say for example a 12cm diameter diaphragm is not anywhere near as great as that of the more modern donor car that is in the vicinity of 20cm diameter diaphragm.

I can tell you now that a TA22 booster, camry master cylinder and hilux calipers lead to a fairly short "hard" pedal (some like it and most get used to it). I have no doubt what so ever that a larger booster would make the pedal feel much closer to that found in the hilux from where the calipers originated - good pedal feel but with a little less effort.

Jack, you should have room (and the fab skills) to fit a larger booster into your car. Just go for one that has a 1" master cylinder already on it.

[WDE_BDY]

I think the master may be too big, similar problems if you look through the Skyline upgrades for the MA61 etc. Overall piston area is not that much different to standard, a 15/16th master could well be a better choice.

Callum

[mrshin]

Pretty much a matter of what you can handle - personally, I like the hard pedal, but those who aren't expecting it think that the brakes don't work...

Worried about left leg not doing enough work? Then fit a decent clutch!

[TA22 1MZ]

Jack, you should have room (and the fab skills) to fit a larger booster into your car. Just go for one that has a 1" master cylinder already on it.

Very true mate. I got the booster with the M/C, just a matter of time and playing around with it get it in. May have to look at theclutch master as well cos initial inspection looked like the booster would foul on it. Nothing a bit of "panel beating" wont fix.

I can get use to the non-assist braking pedal feel, but would also be nice to taps the brakes and get some response. When the pedal is that hard you gotta jump on it to brake, it becomes a very very fine line between effective braking and locking up the fronts!

[YLD-16L]

People would find if they combine the Camry caliper and the Camry M/C with the TA-22 booster the pedal pressure would match that of the original donor car.

To think of this in reverse, fit the TA22 booster to the Camry. I think you'll find the pedal will take a lot more effort to travel the same distance as it would have with the Camry booster

Most items in cars have become smaller in physical size and more efficient over the years. The vacuum assisted brake booster is one item that increased in size since those items found in 1970's vehicles. Don't you think if the nice tiny booster found in a TA22 or KE30 could offer the same pedal feel as the much larger unit found in a Camry then Toyota would use the smaller item

I can get use to the non-assist braking pedal feel, but would also be nice to taps the brakes and get some response. When the pedal is that hard you gotta jump on it to brake, it becomes a very very fine line between effective braking and locking up the fronts!

That's exactly it Jack, everyone wants to achieve brake modulation that they are happy with. Caliper piston diameter and number of pistons/master cylinder bore/booster size all effect the final result.

I think when people get a good setup they should let everyone know so they don't have to go through the whole trial and error process.