Hi All, I have fitted a ST205 servo and M/cyl to my ST165 and have got a few issues
since bleeding the brakes through I have found the peddle to be rock solid, a novelty for a ST165
Problem being when out on the road the peddle doesn't have much effect on the brakes
I mean He-Man may get them to work?

Im wondering if the Servo is at fault, when pressure is applied to the brake peddle and the car is started the peddle does not drop at all?

Another pointer is I believe the servo/cyl to be from a non abs equipped car and it came with a bracket that bolts to the servo and enables the connection of three pipes.
I have utilised this and blocked off the bottom union as there is no need for it.
afaik this is just a junction for the pipes to meet and obtain the angles required?

Any pointers/ideas Very much appreciated

_________________
Steve Gillies
ST-165 88 UK

www.GT4-Play.co.uk

Are you sure the brakes have been fully bled Steve? Might have a stubborn air lock....

Hi Steve, I have seen no more air in the system.
imo if there was air the peddle would be spongy?

_________________
Steve Gillies
ST-165 88 UK

www.GT4-Play.co.uk

Steve - are you confident you have the pipes in the right holes? Can have a look if you need to confirm, have an abs and a non abs 205

_________________
Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

Hi kris, this thought did cross my mind.
I have retained the nicely bent pipe that comes out of the top end of the M/Cyl then curls under the cyl and into the three way block.
I have blanked the bottom hole as i have no need for it.

it then goes from there to a line on th bulk head (st165) stock lines
the other pipe comes out of the side and joins onto the stock st165 pipe.


no leaks have been found.
much appreciated if you can shed some further lights on this little problem?

_________________
Steve Gillies
ST-165 88 UK

www.GT4-Play.co.uk

Silly question but is the servo vac hose okay, fitted right.

after running the engine try pulling the pipe out of the servo. there should be resistance when you pull it out (over coming the vac in the servo(hiss)).

no resistance no hiss its's probably leaking..

is the plunger in right in the rear of the master?

_________________
1990 JDM ST185 Grey.
ST205 head gasket.
ARP head bolts.
ST205 Koyo Rad. (almost)
Front mount intercooler.
Colder plugs.
3" decat pipe.
4 Branch manifold.
Nitrous Oxide Steroids for Cars!

Hi, tbh i haven't heard any hiss when pulling the vac hose no, used to with my old st165 servo/cyl assembly.

i tried the st165 vac line also but that has the one way valve init unlike the 205 unit which by the looks of it has the valve built into the servo assembly, can any one confirm this?

thanks for the reply

_________________
Steve Gillies
ST-165 88 UK

www.GT4-Play.co.uk

Sorry, The system bled all ok so i can only assume the plunger/rod is located correctly.
when bleeding the system the peddle also went to the floor with a bleed nipple open.

_________________
Steve Gillies
ST-165 88 UK

www.GT4-Play.co.uk

Er,

Do I remember rightly that you were having some idling issues too?

Could be a split diaphragm.....
Pull the vac pipe off. If the engine idles exactly the same then there's yer problem

All the symptoms point to this

Cheers steve, will try this..

thanks again to all

_________________
Steve Gillies
ST-165 88 UK

www.GT4-Play.co.uk

Hi Guys, Been working on the car and have found if i suck on the vac line of the ST165 Servo i can 'feel' a diaphram and I'm unable to draw any more air through.
If i do this on the ST205 Servo i can easily draw breath after breath through.

Can some confirm if theres does this for me?
Im aware this sounds like the likely cause but taking this off the car again is no easy quick task, and would like to be 100% sure before i buy another etc

much appreciated

_________________
Steve Gillies
ST-165 88 UK

www.GT4-Play.co.uk

Well i cant confirm that as a trait of the 205 but as a rule the servo needs to hold a vac until the peddle is pressed which allows the servo to assist braking by transfering air from one side of the diaphram to the other.

i would say the servo is dud the one way valve allows vac to be drawn but not air back in to the servo.

_________________
1990 JDM ST185 Grey.
ST205 head gasket.
ARP head bolts.
ST205 Koyo Rad. (almost)
Front mount intercooler.
Colder plugs.
3" decat pipe.
4 Branch manifold.
Nitrous Oxide Steroids for Cars!

Thanks for the reply.
What i can't understand though is if the diaphram was split the car would not idle at all, due to the AFM?

_________________
Steve Gillies
ST-165 88 UK

www.GT4-Play.co.uk

From 93 workshop manual.

TESTING
POWER BRAKE UNIT
Functional Test
1) Start engine. Turn ignition off. Depress brake pedal
several times. Depress pedal firmly and hold for 15 seconds. If pedal
sinks, master cylinder, brakeline or caliper piston is faulty.
2) Start engine with pedal depressed. If pedal sinks
slightly, vacuum unit is working properly. If pedal height does not
vary, power brake unit or check valve is faulty. Replace as necessary.
Leak Test
1) Depress brake pedal with engine running. Hold brake pedal
depressed position, and turn ignition off. If pedal height does
vary within 30 seconds, vacuum booster is okay. If pedal height
changes, check for air leaks.
2) With engine stopped, depress brake pedal several times
using normal pressure. Pedal height should be low when first
depressed. On consecutive applications, pedal height should gradually
increase. If pedal height does not increase, check for air leaks.


POWER BRAKE UNIT PUSH ROD
Check and adjust clearance between power brake unit push rod
and master cylinder piston if either unit is replaced or overhauled.
See Fig. 2. If clearance is not zero, adjust male portion of push rod
using open-end wrench while holding female portion of push rod with
pliers.
Fig. 2: Measuring Clearance Between Master Cylinder Piston & Power
Brake Unit Push Rod
Courtesy of Toyota Motor Sales, U.S.A., Inc.
STOPLIGHT SWITCH
Remove lower instrument panel and air duct (if necessary).
Loosen lock nut. Turn switch until clearance between switch and pedal
stop is .02-.09" (.5-2.3 mm). See Fig. 1. Check brake pedal height.
See BRAKE PEDAL HEIGHT under ADJUSTMENTS. Check brakelight operation.



If the rod length is wrong it could be releasing vac pressure...maybe?

_________________
1990 JDM ST185 Grey.
ST205 head gasket.
ARP head bolts.
ST205 Koyo Rad. (almost)
Front mount intercooler.
Colder plugs.
3" decat pipe.
4 Branch manifold.
Nitrous Oxide Steroids for Cars!

i have had it before where a slight leak on the servo didn't cause more than a poor mixture it ran ok at idle.

O2 sensor just kept telling ECU more juice man and the ECU was pumping it in till it maxed out.

try running the engine and spraying the servo with some thing like WD40 if there is a leak on the case the revs should change and you may get some blue smoke from the tail..

PS i wouldn't want it to be the servo either nothing worse than having to take off a bit you just put on!

_________________
1990 JDM ST185 Grey.
ST205 head gasket.
ARP head bolts.
ST205 Koyo Rad. (almost)
Front mount intercooler.
Colder plugs.
3" decat pipe.
4 Branch manifold.
Nitrous Oxide Steroids for Cars!