Board logo

Brake Pedal Travel Problem
Jeffers_S13 - 6/6/05 at 08:56 AM

Got my brakes filled and bled on Saturday, there is no air at all in the lines and I have no leaks.

The car stops, not very well, but I guess because they need bedding in. BUT, there is absoultely loads of travel in the pedal before anything happens, does anyone else have this problem ?

I have M16 calipers at front on a 5/8 master and I have 9" drums and appropriate cylinders on back with a 3/4 master and a balance bar set-up. Is my only option to fit bigger bore masyer cylinders ? or have I made some classic mistake ?

James

Edit, before anyone suggests it, the calipers are on the right way around, spent a while scratching my head on Sat afternoon wondering why there was no brake effort at all...yes bleed nipple at the TOP so the frickin trapped air can get out, few messy minutes later and that was sorted.

[Edited on 6/6/05 by Jeffers_S13]


NS Dev - 6/6/05 at 09:45 AM

what state are the automatic adjusters on the rear drum setup in?

Your setup sounds spot on so the only thing I can think of, which is pretty common, is that the shoes are retracting too far because the auto-adjusters aren't working.

Take the drums off and manually wind the adjusters out until you can only just get the drums on, and try it at that, should shorten the pedal travel.


Jeffers_S13 - 6/6/05 at 09:47 AM

I dont know, I just kind of put them on, a good few months ago now. I just thought they'd ratchet themselves as I started to work the pedal, but will do this tonight, bah another 6 hrs of the work yet though


britishtrident - 6/6/05 at 07:52 PM

Slacken the hanbrake cable fully back to ensure the self adjusters have enough free movement to operate.

However from your description and becasuse you have such a large bore mastercylinder on the rear bralkes it sounds to me like the problem might lie somewhere else -- are the pistons in both calipers moving ? it might seem strange put a stuck piston (or pad) on an M16 style caliper will cause a spongey brake pedal -- this is because the caliper mounting is forced to act like a spring, strangely it dosent affect the stopping power much until the pads are well worn. The quick way to check for this is to get an assistant to pump the brake on a off while you rest a had on the caliper and the disc --- if you feel ANY movement of the caliper at all this is the cause of your problem.

If that isn't the case is everything in the pedal box and mechanism sufficiently ridgid ? -- nothing flexing excessive ?

[Edited on 6/6/05 by britishtrident]

[Edited on 7/6/05 by britishtrident]


Hornet - 7/6/05 at 07:07 AM

I was worried about this m8.... I used the servo and master cylinder from a mk 2 escort. My foot seems to travel for ages before brakes kick in.... but brakes passed all tests during SVA last week.. so, as long as they work, they might be ok.

Cheers


Jeffers_S13 - 7/6/05 at 07:43 AM

Right, I wound the 'self' adjusters around manually last night about 2-3 turns ! so the drum only just fit over them. The brake pedal is much better but still not brilliant, there is still quite a lot of travel, maybe its normal, although I didnt have an assistant last night to watch what the balance bar was doing, so now it may not stay straight after pressure has been applied. Both rear cylinders work OK, I will need to check the fronts are working when one of me housemates is around. But spent the rest of the night constructively by driving it up and down the yard then made a battery strap, so I can give it some more beans on Wednesday when Im on it next

Thanks for the help

James


NS Dev - 7/6/05 at 08:18 AM

If the pedal is better, then you really need to try bedding the brakes in a bit, this will probably make a further improvement.

If they are new shoes and drums, they take a while to "fit" to each other, and will tend to give you a springy pedal for the first few miles.

Get everything bedded in nicely then review the situation, and re-bleed the brakes again, then all should be ok.


Jeffers_S13 - 7/6/05 at 08:25 AM

Yeah I expect wear to account for some of the spongy feel and travel, it just seems excessive, I'll have to wait and see I reckon.