What are your sierra brakes like?? I need help plz

[JrZook]

Gday all,
I have a 85 drover swb,Ive have never had good brakes on it, ie a low spongey pedal with not to much power assistance just a hard pedal . I have a new master cylinder, new rear cylinders/shoes, kitted the front calipiers/pads. I have also replaced the porportioning value. I have set up the rear shoes manually as those 'auto' adjusters are crap. Now i have tried clamping off brake lines to find the problem. When the rears are clamped off the pedal does rise quite a bit tho just clamping the fronts off will also have the same result. So im stumped. Could it be because of the old rubber hoses expanding??? Any suggestions as crazy as they mite seem would be great. What other adjustments can i make??
Cheers Dan

[Bad JuJu]

Check you don't have an air leak in the booster diaphram or as you say buggered soft break lines.
Is there any sign of a leak??
Are you sure there is no air in the lines?

[sierrajim]

Do you have extended brake lines? if so your brake pedal will not be any where near as good as factory length lines. Fix, braided brake lines (note- these are not roadworthy)

Are you sure its the right booster for the car?

If not above,

Check for vaccum leak in the booster if you have the necessary tools

If not above,

Flush your old brake fluid out of the system by way of a MAJOR brake bleed. (worth doing anyway, brake fluid is supposed to be done every 80-100,000 km for normal road use)

If not above,

Spray something like carby clean on all brake line connections, joins, fittings, wheel cylynders etc. The have someone pump up the brake pedal hold it down for a while and check for leaks.

[84ZOOKSTA]

Did you say you have a booster???

Lucky you.

My 1984 SJ410 1.0 has nothing like that so it's hard work to make them operate.

Does sound like air in the system but i am not an expert on brakes.

Cheers

[sierrajim]

My 1984 SJ410 1.0 has nothing like that so it's hard work to make them operate.

Disc or drum front? Just put discs on mine, WOW it stops.

[84ZOOKSTA]

I have discs.

It does stop. I just drive a new VW normally and that stops great.

[ofr57]

i just thought ..... could your discs/ drums could be warped .... meaning they need to be machined or replaced

easy to check though

[Spike_Sierra]

just going back to the rear drums, make sure the adjuster doesnt come out of its tracks and go above the small circle bit. this happens when theres alot of slack on the half circle slide adjuster, my fix to this was weld a small bit ontop of the small circle to hold the semi circle in place, but still alow it to move.

and before you put evertthing back on, try gently pumping the pedal to make sure its all working.

this is what happened to mine, and it would need two pumps to get anywhere, as the adjuster was coming loose, so it would need more fluid to actually get it anywhere near the drums.

hope it helps.
can draw diagram if you are lost

[JrZook]

The booster is original and hasn't been tampered with yet.............. ThE booster still holds vaccume bout 4 pumps until its emtpy with the engine off. There are no brake fluid leaks and the fluid has been flushed through a few times now. Drums and discs are still within service limits and brakelines are origional. Does anyone has a pic of the rear 'working' drum brakes with the auto adjuster setup? Has anyone had brake line probs b4??
Cheers Dan

[foolsp33d]

not helpful... but stock on mine they came in at 80% on the roady.....

[built4thrashing]

why dont you upgrade the front discs to vented lwb vitara discs and calipers. an easy conversion and simple to do.

[Zute]

My brakes were like yours. Had front discs machined and replaced rear shoes, cleaned up adjusters so they looked new. And now it all works.
Don't try and set the auto adjusters, just make sure they move freely. Soaked mine in diesel and scrubbed them with a tooth brush. Fit them, than reverse at speed and hit the brakes. This helps them to work/adjust. May need to do it a couple of times.
Good luck.