Having replaced front calipers/pads and bled system, have encountered a problem:

Pedal travel is now much greater than before (fairly stiff with engine off, drops when engine running as normal but travels too much before brakes bind). Only tested at low speeds and car does come to a stop, but worried that I might have bigger problems on the open road. Plus warning light came on once, but only once.

And if anyone is going to suggest master cylinder, I would be at least a week away from getting the part, so can they be dismantled and overhauled without the need for seals/other parts etc (bit of a long shot I know).

BTW, tried Lucid's trick of blocking the brake pedal to prevent fluid loss, it works a treat!!

Thanks

Did you replace the Front calipers? If so, there should be two "match marks" on the bottom of each one, to show that the remanned unit was correctly assembled. Look for a good-sized punched "dimple" on each side of the center joint.

Actually, it's easier to check the top end of the calipers. There should be NO punch marks on a good one.

Mis-Matches DO happen. I have one from a boneyard that looked great, but it wouldn't bleed out properly.
--
Bruce Young,
'93 940-NA (current), '80 GLE V8 (Sold), '86 240dl, '85 244 ti, '83 245t
'76 244 (R.I.P at 255k), 73 142 (98K), '71 144 (ex circle track car)
Used '70 144 from '78 to '92, New 144 from '67 to '78, Used '62 122 from '63 to '67

If you did any pumping of the brakes while you had one of the valves open, and I mean even ONCE, you probably toasted your old MC. MCs get pretty gunked up beyond their normal length of travel, and if you pump the brakes further than they usually go, you slide the weak piston seal across the corroded part of the cylinder, causing it to leak. It's a very common thing to happen, and to prevent it you just have to make sure that when you have the valves open for bleeding you never step on the brake below where it usually stops when the system is closed. This would include even the one time you press the pedal all the way down to prevent fluid loss.

And no, you can't rebuild them without the new seals, since it's the seals that give up the ghost (hopefully not yours).

I don't know how bad your problem is and what your driving conditions are, so it's hard to recommend any course of action beyond the standard warning of never to drive when the brakes are in doubt at all. Having said that, I once had VW bug with a weak master cylinder that I was able to nurse along carefully by pumping the brakes to get full pressure when I needed to. It got me through a few days before the rebuild kit came, and I guess I got lucky that I didn't have to make any sudden stops at high speeds (and besides, the MC was only marginally bad, it did stop the car even without pumping). I wouldn't recommend this course of action to anybody, however. If you value your life much (I suppose I didn't back then), take the bus.

" This would include even the one time you press the pedal all the way down to prevent fluid loss."

On the 240s, my tip was to depress the pedal just an inch or so, not all the way. No risk to the MC at all.

The Volvo 900 Brake manual says only to "depress the brake pedal" (using a Volvo shop tool), but doesn't say how far. The drawing makes it look like all the way. But there is no warning given about "too far".

My only 900 experience is that the 1" or so that works on 240s isn't far enough on the 900.
--
Bruce Young,
'93 940-NA (current), '80 GLE V8 (Sold), '86 240dl, '85 244 ti, '83 245t
'76 244 (R.I.P at 255k), 73 142 (98K), '71 144 (ex circle track car)
Used '70 144 from '78 to '92, New 144 from '67 to '78, Used '62 122 from '63 to '67

Thanks for your feedback. At least I know about this for next time. I'm ordering replacement M/Cyl, as better safe than sorry...

I would suggest the MC. old ones don't seem to hold up well after bleeding brakes. You can probably get a rebuilt one locally for a decent price, then just pop it on, bleed it properly then bleed the system.

good luck on whatever it is.
--
'88 244 171K, '87 BMW 325e 172K (used to feed a '84 245 'till 227K)

Sounds like you have air in the system. Did you bleed using a pressure bleeder? Motive products has a cool one for ~45 bucks, well worth it. Bleeding by pumping the brake pedal is hard with a 240. Secondly, if you did bleed with the brake pedal pumping technique, you may have finished off the MC. FCP has OEM MC's at a good price, even includes the fluid holder. Good luck.