Reverse bleeding through the bleed screw and back up to the reservoir has been used here with success. You need a syringe and a length of tubing and push the fluid upwards to the reservoir and the bubbles will follow up.
There are mechanical reasons why brakes will feel spongy even with no air in the system.
Calipers not free floating on the pins. This will cause the caliper piston to push against one side of the rotor and trying to warp the rotor.
Caliper pistons partially seized
And one of my favorites. Brake pads with the brake surface not parallel with the backing plate of the pads. I just put a brand new set of Brembo's on the wife's Lincoln MKX and the best peddle I could get was at half travel. I really thought I'd lost it. 2 days later the pads settled in and the brakes were rock solid at about 1/2" depressed.
That reminded me of previous days and finding pads half scruffed in . measured with a vernier and the pad material across the face was out almost .050". Crazy !!
A little trick I have used recently is to attach a syringe to the bleed nipple and draw the brake fluid through, bleed the left calliper first if you use transparent hose you will be see the air coming out.
Make sure you keep topping up the reservoir as it can empty quicker than normal bleeding if a large syringe is used.
scotch wrote: Suggestion #1 - Don't forget to remove the zip-tie !
#2 - If everything else is mechanically sound, then you still have air in the system.
#3 - This can also be attributed to the OEM rubber brake lines which were crap from the day they were made !
If they're originals, they a garbage and maybe even dangerous !
Hello Scotch... thanks in advance for all your great posts! they are a goldmine of great tips, tricks, methods, madness, all kinds of awesomeness! I'm just getting my 13 back together and truly appreciate all the info on this site. Regarding the brake lines, any thoughts on the best replacement. I know stock set up is available 3 lines (1 into 2) and see the 2 line conversions with a longer double drilled flow bolt. The PTFE inner tube has to be a whole different world from the stock EPDM inner with braided string. Even a brand new OEM replacement line cant compare on expansion. Any thoughts on best approach? OEM replacement, 3 line Teflon, 2 line Teflon conversion, or some other awesome set up! Thanks! Mike
80 KDX 175
2003 KDX 220
2001 Gas Gas 300
mlyle11 : Can't really advise with any purchase experience as I made my own S/S braided lines, many years ago. At the time I couldn't afford commercially available lines but my brother worked at a shop that among other things specialized in hydraulics so bought some bulk S/S line along with the compression fittings. I removed the banjo fittings from the OEM's, cut them off at the major diameter, brazed them to the new compression fittings and had the shop crimp them. They haven't blown-up yet so must have done something right !
Many line-kits are available through various sources
Purchased one of these vacuum pumps a few years ago and it works well for bleeding brakes
Then..........Came across a discarded kitchen vacuum bagger and had a "scotch" moment,
Works brilliantly! With a Tee fitting, I can bleed both front calipers simultaneously, in one shot, but really have to pay attention to the reservoir level !
The pump will draw down to 20" Hg. Not shown is a vacuum gauge I connect, to adjust the Yellow knob which is a needle-valve that controls the vacuum. 1.5"HG to 2" Hg vacuum, is the best range to remove fluid/air, but not so fast I loose the reservoir, too quickly. When the last of the air is drawn out I keep the pump running, shut off the bleeder nipples, then turn off the pump.
1980 KZ 1300 sr# KZT30A-009997
Always High - Know Fear !
The following user(s) said Thank You: biltonjim, zed_thirteen, Kawboy, mlyle11
One thing that can help is countersinking the hole in the end of the banjo bolts. The end of the bolt creates a 'shoulder' that can trap air bubbles and countersinking the end eliminates (or dramatically reduces) the shoulder.
Alternatively, 'Bolt bleeding' solves the trapped air problem but that's a bit of a messy option (and hard on paint if using DOT 3, 4, 5.1). The banjo bolts in my old Honda are countersunk from the Factory.