87 stiff breaking

[p7387]

hello all
1987 r10 2wd 305

i am experiencing very stiff breaking, when i depress the break pedal with an amount of force that would normally create a skid the pedal is very stiff and hard but will eventually come to a stop. (pedal does not go to the floor)

i do not see evidence of obvious leaking but the front small rectangular reservoir keeps sucking the diaphragm off one side of its rubber flange (the diaphragm looks slightly deformed on one side) over time the fluid escapes from the reservoir but again i see no signs of leaking?

note-i wanted to try and replace the front small rectangular diaphragm but it seems to be very hard to find
i will create a separate post on that topic

thanks

[p7387]

i have an 87 r10 2wd with breaking issues (separate post)
i was looking to replace the diaphragm in the front square small reservoir but all the parts stores i called cant even find a schematic showing that part?

rock auto and carID only show the larger reservoir

any suggestions will be appreciated

thanks

[ehjorten]

Maybe it is just a spell-check, but they are brakes, not breaks.

I am not sure what rectangular diaphram you are talking about, but it sounds like you have lost your power-assist.

[VileZambonie]

agreed, you need to spell the parts correctly if you are searching for them especially if you are searching for "break" parts.

Sounds like maybe you have a hydro-boost system? Take a pic

Pump the pedal firmly several times and with your foot on the brake pedal start the engine. Does the pedal move?

[p7387]

Ok
Will do and report findings along with pic
Thanks

[p7387]

hey vile

yes the brake pedal moves when i apply pressure and start the motor

see the attached pictures, note the smaller rubber diaphragm deformed seating, its constantly being sucked off its edges

thanks for the help

[Irish_Alley]

what am i looking at, it hurts me brain. no seriously i never seen this setup before. this is a truck from the states right?

[cvbear]

I have seen hundreds of these trucks and never seen a Master Cylinder setup like that.  Maybe one of the more experienced members can look at the pictures and tell us about it.

[Irish_Alley]

is your booster vacuum line hooked up?

[Captkaos]

Actually everyone here that has seen my Camo K5 has see at least one.  It had that one it before I converted to diesel.  They weren't that popular from my experience.


You are having hard pedal and you are loosing fluid?

[VileZambonie]

That's a chevy astro van master cylinder. Get the correct one for your truck and order it with reservoir.

[nazielinski]

It mighr not hurt to put a booster on it check the vacuum lines also one could be clogged and causing your assist to not work and how fast are you loosing fluid

sent from my fingers

[enaberif]

That's a chevy astro van master cylinder. Get the correct one for your truck and order it with reservoir.

Well ain't you just a wealth of knowledge

http://powerbrakeservice.net/chasvan1hyma.html

[p7387]

chevy astro van? so that explains why the part doesn't show up under an 87 r10 search.
i found a place to buy the small square rubber bladder, i will try that and see what happens.
if i end up replacing the mc/booster with a correct one will it fit basically the same?
is this a straight forward job or tricky?

i checked around the booster, the hoses look good with no obvious vacuum leaking.
just curious? i see no mechanical link between the foot pedal and the booster itself, is it behind the firewall?
thanks

[VileZambonie]

The actuator rod is connected to the pedal assembly. Just get the correct booster/master combo for your truck. It's fairly easy to replace.