Brakes staying on after driving a while

series 2 e type, brakes work fine for a while when driving then did not release. although the pedal feels normal. car sat overnight and the brakes were released. would this point to the reaction valve. entire brake system is new,

This often happens with a brake hose that has come apart and collapsed inside. The hose looks normal from the outside. The collapse acts like a one-way valve not letting the fluid back into the caliper to free the brakes.

You mention the entire brake system is new, but sometime folks forget to change the flexible hoses. If you find this is the cause of your problem, get a new set (fronts and rears) of flexible hoses or better yet get the braided kind which have teflon (?) innards which wont collapse.

…or… more than likely…

one of the three rubber brake lines is old and swollen inside. That is not uncommon, happened to me twice so far on the Jag. If that is the case, just replace all 3, they are cheap.

LLoyd

In order to keep our big corporations prosperous, make the one percenters richer, and give the working class the artificial impression of prosperity, we require a small, controlled war in at least one country at all times.
LLoyd 2006

Although the hoses are a likely suspect, I would take the time to determine which corner(s) are dragging. Create the situation and then, before things settle down, raise each side of the car and see which wheels are not free.

Doing this may point you to the hoses (e.g. one front sticks, only the rears stick) or suggest something else is amiss.

FWIW - I replaced with braided hoses up front as I think they give a firmer pedal but stayed with the rubber hose in back so I could disable the rears with a simple clamp if a problem were to occur back there while travelling.

I would also check the free play on the master cylinder to make sure it isn’t closing up with heat.

IR temperature guns are quite cheap these days. Just point and shoot after a drive. Compare brake rotors. You may also have a sticking caliper piston.

just thinking about a inferred heat gun. easily could determine which brake calipers were hotter. it did seem like the right rear. and their was some smoke on the right side. the car has been sitting a long time during restoration. so all of your ideas could be possible.

So also throw into the mix a confirmation that the handbrake isn’t dragging.

these are all possibilities, sunday is the day to check this out

drove the car and after 10 min. the brakes again started staying on, the front brakes are cool but both rear rotors are hot around 250 degrees. brake pedal is hard. could be the brake hose to the rear, would not think its a puck sticking because it is both rear rotors. I would also think its not the reaction valve or servo because its only the back, any thoughts guys

I think you’re on the right track suspecting that hose… but I would back off (or disconnect) the handbrake adjustment just to be sure that it is not what’s dragging.

backing off the handbrake is an easy experiment, ordering a new braided hose also.

I’m having a similar issue with my 420 which has the identical braking system as the series II Etype. All of my components are new down to the rubber hoses. I’ve been told that there was a bad run of “new” master cylinders from the usuals and this could cause the brakes hanging up as well. I’m going to get an original master rebuilt and see how that goes.

process of elimination,

Drook,

I think the key here is that mrferrari (by the way, wouldn’t it be nice if all you folks used a real name? Just add it to your profile) found that only the rear brakes were stuck on. Have you done a similar check? I would have thought that a master cylinder fault would tend to lock all brakes equally.

-David

master cylinder operates the front and rear separately. so the mc could be the culprit. I am going to try pumping the brake like 20 times engine running but sitting still, that should cause the brakes to stay on. if its a hose or the mc. I rebuilt my original mc myself, going to replace the hose first since that’s the easiest thing to try and cut the old hose open to see if its failing inside. also going to check the handbrakes out,

Have you checked that there is the correct free play on the rod going into the mc as I suggested?

not yet but I will later today

Disconnect the vacuum hose from the booster when it’s dragging and see if it releases. I inherited a similar problem from the PO of my Series 2. He told me about it and had already changed the front brake hoses and said he hadn’t had time to reconnect the vacuum (I guess if he figured out it was vacuum related, he should have known it wasn’t the brake hoses.) I drove it home without power assist, reconnected the vacuum line and the brakes dragged. Changing all the vacuum hoses around the booster and vacuum tank took care of it for me

yes that would be another idea to check out, if it was the brake booster wouldn’t that affect all 4 brakes not just the rear 2. but that will be one thing to check out for sure,