Reverse brake bleed 1st timer?

[muzikill]

So i did the following used from the hel site. btw is a one line front system.

"For this you will need a large syringe filled with new fresh brake fluid and a tube which fits the bleed nipple & the syringe. Connect the syringetube the blled nipple and open the bleed nipple SLOWLY push the brake fluid in through the caliper up to the master cylinder (which is bleeding in reverse) Do the caliper furthert from the master cylinder first and then the other one. Repeat if necessary and keep checking the reservoir level so you do not overfill the system. This way ALL AIR IS PUSHED UP AND OUT OF THE SYSTEM meaning bleeding is much easier than trying to push air DOWNWARDS and out of the system in conventional bleeding BUT please do not exert massive pressure at the caliper as this can pop the seals etc."

It didnt say what way the brake lever should be and i think i did it without the lever being tied in. So should i prime the lever as followed?
"Bleed the master cylinder alone first by pumping the lever a few times then opening momentarily the banjo bolt at the master cylinder end whilst squeezing slowly inwards. Don't release before closing banjo. Put plenty of rags so you don't spill over the nice paintwork."

I've also notice that people who have reverse bled then do a part normal bleed (probably to get the last of the air out of the calipers)

The reason i ask is i did the reverse bleed as instruction in the first paragraph i posted but the brake lever has no pressure on it. I iwas to revert to using other methods do i have to open the nipples on both sides at the same time, connect a tube to each one and dip them both in a jam jar filled with fluid? Im worried that the air is trapper somewhere at the braided hose t junction before it drops down to the calipers also i suspect there is air trapped at the area where the lever piston is.

the brake lever would have to be out (off) too allow the fluid to flow back into the resevoir.

it sounds like a very messy, complicated and awkward way of performing a simple task. If you are having bother with air in the system, loosen the calipers and the 'T' fitting and jiggle them about as you do a normal bleed i.e pumping downwards from the lever. This will let any bubbles float up and round to the nipple on the caliper.
I have to do this on my Lotus as the 4 pot calipers always collect air on the side that has no nipple fitted. unbolting the caliper and rotating it slightly to let the air bubble towards the side with the nipple fixes the problem nicely.

another way is to: perfrom a normal bleed, remove the pads, pump the pistons on fairly far out (but not all the way obviously) and squeeze them all the way 'home' with a flat lever. there is more than enough volume in the calipers to displace all the fluid out of the lines and the master cylinder back to the resevoir and therfor would flush any air back upwards.

Cheers,

[Bibio]

the way i have always done it:

down and over system..
bleed the longest hose (from MC) first then the over.

split system..
doesn't matter but i have always done the right side (offside) then the left side

two line system (race)..
i have always bled the line with the banjo nearest the MC first till fluid flows then do same to other side then a final bleed.

for fresh dry systems i use a hand held vacuum pump and a 1 way bleed bottle.

to make a one way bleed bottle... take a tough plastic bottle or glass jam jar and punch/drill a hole in the cap/top of the bottle slightly less diameter than the hose you are going to use then force/squeeze the hose all the way down to the bottom of the bottle/jar then cut end of hose at 45degree. make another hole like the previous one and insert another hose about there is about 10-15mm inside the bottle/jar (make this hose long enough that you can stand up and watch the MC level), this hose becomes the one that you attach a vacuum pump/syringe to.

if you don't have a vacuum pump then you can use a syringe to suck.

once you have fluid coming out of both callipers then disconnect vacuum pump/syringe and bleed in the normal fashion.

to dislodge trapped air bubbles then tap callipers and lines lightly with plastic end of a screwdriver while you are bleeding the system.

[embee]

I think the biggest issue with "reverse bleeding" is that bleed nipples are always at the top of caliper cylinders and the line to the master cylider enters at the bottom. They are this way because they are designed to be bled in the "forward" direction.

Trying to force fluid into the bleed nipple means you are expecting any air in the caliper to find its way down to the bottom in order to then go up the hose.

It's usually a similar issue up at the master cylinder too, the outlet from the cylinder is usually at a high point, so you are trying to get air to go downwards through the cylinder.

In conventional forward bleeding the air in the master cyl will naturally get to the outlet hose which is a small enough diameter that the air will stay in a bubble and be carried along with the fluid by the relatively high velocity during bleeding. Once it gets to a larger volume (master cyl or caliper) it tends not to be carried with the flow so you need buoyancy to help it to the outlet, which is why it's at the top.

Vacuum bleeder are my choice, Mityvac or equivalent. Very easy to use and very effective because you can maintain a steady flow to draw the bubbles through the hoses.

[muzikill]

Ive got both calipers reverse filled from the bleed screws up to the reservoir. Did the 'gear' side caliper first until I could see the reservoir starting to fill after much bubbles of air. Closed the bleed screw. The n reverse filled the other caliper 'brake lever' side took a medium bit of force taking care not to blow the seals. Reservoir filled up more with medium bubbling, stopped occasionally to remove some fluid from the reservoir and continued until the bubbles stopped. This was done with the brake lever open. Still left with no lever tightness at all. Would there be air up at the lever? And after this should I do a normal bleed at each caliper to push out remaining air at each caliper?

[Bibio]

not trying to be funny buuut. have you pumped the pads against the disc?

[muzikill]

I did & have. Working . After I used the reverse method to initially fill it I did a 'proper' bleed with a jam jar. Furthest caliper away first and nearest one last the furthest still had bubbles and I could hear them gurgle their way into the caliper and out the tube. The nearest was done last and tbh there wasnt much but I bled it for a bit to make sure. Then I checked it all over and pumped the brake lever so the pistons would seat. Checked the reservoir level as I went along and topped it up. Seems sorted. The calipers have a teeny bit of play on them when the lever isnt pulled on but I think that will dissapear when the pads bed in. You think it should get another bleed after a short run? If not im a happy chap. Ive just got the rear to bleed next.

That means muz can rebuild the sv calipers, fit new lines and bleed them.

Anyone else reading, the time I wasted was through learning. I'd easily recommend reverse bleeding to prime it so theres minimal air in it all.

Open, pull, close, release, check. Etc.. Lol.

Bibio & everyone else, thanks again for the support.

[Bibio]

i usually do a final bleed when the pads have settled in about 100 miles and the day after (not right after a ride). the vibrations from the road usually send the remaining bubbles trapped in the callipers up to the top ready to be bled out. any bubbles in the lines usually find there way up to the MC.

[muzikill]

Thought as much. Im wondering if a normal bleed is better for the rear now. Its only one line!

[Bibio]

it makes no odds which way you bleed.

tip: once the system has been bled apply a small amount of pressure to the rear brake leaver, while doing this put a rag under the MC banjo bolt and 'crack off' the banjo bolt at the top and let a small amount of fluid escape then tighten up again before you reach full travel on the rear brake leaver. if you let the leaver go down all the way or stop the pressure before tightening the banjo you have to repeat the procedure. reason is that sometimes a small bubble of air gets trapped in and around the banjo.