Strangest thing - Anyone ever heard of this before?

[elanski]

I was using my car this morning for its first proper run of the year. All running as normal until about 5 miles into the journey. Doing 60 about on a duel carriageway car started to (what I thought at the time) lose power. 50, 40, 35....
Came off at the next junction and the car could barely get up the slip road. Crawled up at about 20mph and luckily found a lay by immediately by the junction, so pulled into it. By now the car would barely move.

Once parked, put it in neutral and the engine was revving freely, did not seem to be an obvious engine problem. Tried to pull away again and nothing - Clutch engaged but It was as if there was an invisible force holding my car back. Even if the brakes were on I would have expected some movement.

Checked all round and under the car. Nothing obvious to my untrained eye.
Clutch and brake fluid normal
Clutch movement and gear selection normal
Handbrake definitely off
No unusual smells or noises

Suddenly, sitting back in the car again I felt something release. Car moved about an inch backwards.

Started her up again and edged forwards - everything back to normal. I abandoned my journey and headed straight home. No problems at all.

What on earth might have happened?

I'm thinking something up with the brakes maybe but I was travelling at speed without using them when it happened so its not as if they locked on after pressing the pedal. And all the way home it was fine?

Any ideas what I need to check for?

Feels like something out of the Twilight Zone

[DutchTony]

In my opinion it sounds like that your brakes were not moving back enough and by driving they heated up, so did the discs. That is why you gradually lost power. After stopping everything expanded a little more pushing in the callipers a little. When the discs cooled down, al little play was enough to release your brakes.

[alaric]

Hi. Maybe the handbrake shoes were stuck on. The handbrake tower at the back may need freeing up. Did the foot brake efficiency feel OK throughout?

Sean.

[Billelan]

I had the same issue with my S4 several years ago, it turned out to be the servo. On the roadside I disconnected the vacuum pipe to the servo and all was well until I got home and removed the servo completely.

[types26/36]

Check that the brake master cylinder push rod has some free play and the pedal is not sticking and returns to its rest position when released.

[Hawksfield]

Hi
Servo control piston malfuntion. Is it a Girling

[2cams70]

If the brakes were on it would have generated a lot of heat. I’m surprised you didn’t notice the smell of hot brakes or smoke.

[berni29]

Hi
If your car has a servo, then there is a strong possibility it is the servo sticking. I had a plus 2 that used to do this occasionally. Before fixing it I used to carry a small spanner around with me to release a front calliper bleed valve which was the only way to get it to release.

Best of luck

Berni

[Elan 1600]

A friend had this problem in his modified Elan years ago, and the day to day solution was what Berni recently posted about releasing the pressure and an issue with the servo. In his case the servo had been moved by a previous owner and was adjacent to the exhaust. We suspected the servo was heating up and causing the issue, so we insulated the servo. Problem solved.

[elanski]

Thanks for replies everyone. I've looked at everything suggested and am thinking its something up with the servo. Don't know what made it misbehave but perhaps it didn't like sitting all winter without being used.

But I have an idea of what to investigate further now, so thanks.

[661]

If this is an Elan, I would have thought this is a perfectly trigger to ditch the servo

[Lotus fan]

I had exactly the same issue with the brakes.
It was the small valve ( it looks like a small bullett ) in the servo sticking.
Popped it out, cleaned it up and biingo, all was good.

Ian.

[englishmaninwales]

Lockheed servo in my S3 failed in a similar fashion. Removed it altogether and replaced the front pads with Mintex 1144.

[Rob1n]

Rear or all callipers may have locked on. I had that myself when they cool down a little they release.

[alan.barker]

Lockhead Servo must be fitted at the correct angle.
Alan