I've been driving my newly acquired SE6a around for about a month now and working through the thing I'll need to do to make it a good reliable easy commute car, which in fairness shouldn't be too much. On Friday's drive to work, after a period of enthusiastic driving, the brakes were suddenly replaced by a hissing noise and much reduced stopping power - I limped back home carefully, parked up to investigate when I next could, which will probably be later today/this week.
My first (and only to be honest) thought is that the servo has failed, but before I just blindly order a new one should I look elsewhere - I did quickly check the servo hose and looks to be ok.
Do my symptoms sound obvious?
Any advice appreciated.
Posted: Sun Jul 21, 2019 8:26 am
by peter freeman
Getting a new servo unit is difficult - a repair kit perhaps you can find.
Posted: Sun Jul 21, 2019 9:10 am
Does sound very much like a failed diaphragm, if it was the servo hose you would hear it all the time I would have thought?.
I have a few Lockheed kits left and at least 2 used servo`s.
Where are you?.
Posted: Sat Jul 27, 2019 10:03 am
So I had a chance to poke around yesterday and although the hose from the hose from the manifold was a bit loose, once re-attached and tightened up the noise was exactly the same, so it wasn't that unfortunately. So on testing again, the hissing noise is definitely coming from down at the base of the pedal - when the pedal is pressed it is clearly audible.
Does this make it more diagnosable?
p.s. Mark, I'm in SE London
Posted: Sat Jul 27, 2019 6:06 pm
Surprisingly Joe you will hear a slight hiss when depressing the pedal.
This is the vacuum in the servo working on the diaphragm.
How loud is your Hiss ?. and when does it occur?.
Worryingly is the brakes not working correctly.
After letting it all cool down now, do the brakes still not work as they did?.
Loss of servo is quite rare.
Only asked about your local to see if a visit and butchers could have happened,
Posted: Sat Aug 03, 2019 12:03 pm
It's pretty loud - I've taken a video of it and will try to find a way to upload and share. The brakes still work, but seem a lot less effective and you do have to press the pedal pretty hard. Having had a poke around this morning it seems as if I take the clevis pin out of the brake pedal which should release the piston from inside the car, then from the engine bay I remove the two nuts holding the fluid reservoir to the servo, from there nothing looks obvious but would the servo just slide out into the engine bay for me to investigate further?. Hopefully the fluid reservoir when removed will hold its fluid and not make a mess on the garage floor and when reconnected the system won't need bleeding through. You never know until you start pulling things to pieces but if anyone has done this before some hints on what to do/not do would be much appreciated. Along with an idea of where on the scale of 'Easy to do with a spanner, big hammer and no skill' to a 'don't even think about doing anything other than taking it to a skilled mechanic you idiot' this task would be...
thanks in advance
Posted: Sat Aug 03, 2019 4:23 pm
Servo is bolted through the bulkhead to the drivers firewall.
Undoing the Two nuts inside the engine bay will just remove the Master cylinder FROM the servo.
After all these years the rubber seal for the servo chamber to bulkhead will be very stuck, been there before.
The nuts for the servo body are up inside the pedal box, awkward to see so pull the seat right back and get a good torch.
Posted: Sat Aug 03, 2019 5:26 pm
Also helps to take the steering wheel off! (not to get the nuts off, just to get access )
Posted: Sat Aug 03, 2019 6:38 pm
Ok, I've tried posting the hissy video on youtube, not sure if it will work but if it does then hopefully someone will be able to give me a diagnosis...
Please accept my apologies if it doesn't work and I've just posted a hilarious cat video.
Posted: Sun Aug 04, 2019 8:57 am
Definitely a faulty servo.
Never heard one sound like that though.
Probably a split diaphragm.
I have at least Two spare used servo`s, and Two service kits left if you wanted to repair yours.
Posted: Tue Sep 10, 2019 11:50 pm
Just a quick update on this, Mark, thanks ever so much for the replacement servo which I fitted at the weekend. Pretty easy job and I now have my brakes back, woohoo! I love it when a repair plan comes together.