New front brake calipers bleeding tips?

[sodafeld1]

I have always successfully bleed the brake system on my hj75 very easily with a motive power brake bleeder.
I just installed brand new front calipers, no bubbles are coming out when I bleed but the pedal is spongy and goes to the floor, can pump it a few times and it firms up. No leaks. Must have an air pocket in the new calipers somewhere.

Does anyone have any tricks such as raise the front or back and bleed again?, or take off the calipers again and re install then bleed again.?

I have run over a liter and half through, no bubbles or leaks.

 

[duncanrm]

Are you rear brakes appropriately adjusted, because you dont make hydraulic pressure on the front circuit until the rear circuit is up to pressure. Wind out your rear shoes until they drag a little, both sides, and try again.

If you clamp off the rear soft line.. this will confirm if its the rear causing the issue.

 

[sodafeld1]

That's interesting, the rear brakes were fine before, but I guess it makes sense to re- adjust with new front calipers.

 

[sodafeld1]

That's interesting, the rear brakes were fine before, but I guess it makes sense to re- adjust with new front calipers.

thanks Duncan

 

[jblueridge]

For me the softness was related to the LSPV. Raising the LSPV arm manually got fluid flowing in the "balancing" section of the line. That's where the bubbles were.

 

[coldtaco]

I think there is a bleeder on that valve too

 

[sodafeld1]

yep frigged around with rear brake adjusting, glad I backed them off a tad, lspv bled. My usual set order pattern furthest to closest to master, rear, rear , lspv then front, front. Tried with lspv a few different positions. Bleed with the rear raised and then again with the front raised if the calipers needed a burp. A bit better but not solid.

But with further reading, it can be found that sometimes new calipers come with the pistons a bit stuck to the seals, especially if sitting on the shelves awhile.
So, I did a kind of prime of the caliper cylinders with thin sheets of ply instead of the fairly fresh brake pads in place, teflon sheet or old worn thin brake pads would be better, pumped the caliper cylinders fully open to make sure they travel fully, then compressed the cylinders to contract fully. The stiffest cylinder being the small one near the brake fluid entrance to the caliper. Careful not to mar the rotors. Re bleed.
100% better!

Also read that little micro bubbles may hold onto the the fresh internal surface of the caliper, which is possible, so worth re bleeding again after an extended drive on a bumpy road.

I always buy brake fluid in the 12 packs, never regret having plenty fresh brake fluid.
Sorted.