brake peddle always soft on my sj413

[sj413shay]

i converted my back brakes to disks awhile back and ever since they have been soft and spongy. on my sj i have 2 brake lines going to the back axle from the front, but on some of my mates suzuki's there is box in the middle of the brake lines, any suggestions

[weldingscotty803]

did you bleed the rear calipers properly? by that i mean were the calipers taken off the carrier and placed in the 12 o'clock position and bled? most kits have the calipers in the 10/2 o'clock position which causes air to get trapped in the piston chamber. it catches plenty of people out. if you did the above then did you bleed all the calipers in the correct order, furthest away to the closest one? only other thing i can suggest is to bleed the whole system and replace old fluid for new

[sj413shay]

When I did the conversion I made sure I mounted them at the 12 position and Iv bled the brakes a 4or 5 times but they always go soft and if I pinch the 2 brake lines on the back the pedal goes back to being firm

[clbarclay]

When you re-bled the brakes was more air coming out each time? In which case air is getting in somewhere, or your not getting it all out.

What condition are the hoses in? poor condition bulging hoses would give a sponge feel.

The "box in the middle" sounds like a limiting valve to prevent the rear brakes locking up before the fronts. Not having one shouldn't be a problem with bleeding the brakes.

[sj413shay]

the lines are in good condition and i have brand new stainless steel braided lines going to the calipers, has me puzzled

[Suzukirama]

What calipers have you used. If you can't get any more air out then that's probably because there isn't any. The size of the calipers will be bigger than your original cylinders, So perhaps your brake master cannot displace enough fluid to match that. I am sure some one will tell you what is needed, perhaps a bigger bored or longer stroke master, or brake bias valve or both. I am not quite sure as I haven't done this.

[lamby2009]

i had that problem as it was a worn rear wheel bearing as the disc was pushing the brakes in and out and making the brake spongy so new bearing job done then done it again but this time axle was bent so the disc was out of angle the brake were like a cheese wedge hope this may help as did you bleed all the brakes as i fond it best to leave all the valves open and let gravity take place with them as mine are greeat now after months of spony brakes

[David_LLAMA4x4]

[sj413shay]

cheers for the help Dave, whats really happening is my pedal is going to the floor. but the brakes are not stopping the jeep, i am using sj413 calipers on the back.
when i am going down hills i have to pump the pedal until it goes real hard and then make my way down the hill,

[clbarclay]

Try pinching the front brake pipes like you did with the rears to check whether the rear brakes on their own a giving a firm feel.


We had a couple of very old loading shovels with miss matched brakes after the defunct air over fluid systems were replaced with series LR master cylinders to make the brakes just hydraulic using the existing drum brakes. The wheel cylinders though were rather larger than those in series drum brakes. They always needed double pumping to work the brakes, which was tolerable on an off highway vehicle with a torque converter gearbox which could withstand shifting into reverse and then accelerating to stop them, but defiantly unsafe on a car.

[danotm76]

I had a similar issue, and eventually figured out that where the bleed nipple entered the cylinder bore was not at the top (even though the nipple was).



That's a photo robbed from the internet which shows the issue.

If the calipers mounted at 12 o'clock then you will have this problem.

Removing the calipers and hanging them at an angle so that the bleed nipple is horizontal and coming out of the cylinder bore at the top and re-bleeding them sorted the problem.

Don't forget to wedge the pads to stop the cylinder pushing out.

Or it could be loads of play in the wheel bearings alowing the disk to move and push the pads back, or as already mentioned it could be knackered flexi hoses.

Plenty of people including myself have done the suzuki caliper on the back conversion without problems or spongyness so its probably not the master cylinder

[Chris Ennis]

when i bled mine up i had to take the calipers off and wedge somthing in the middle and hold them up while i bled them.

and you shouldnt have a problem with the master cylinder size as mines an early 410 with no servo and mine will lock the back wheels before the front


chris

[Darrell]

I'm sure you checked when you fitted them, but are the capiler slide pins moving freely.