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Post by dave1800 on Oct 13, 2013 8:15:31 GMT
First we would like to thank all the members who took part in this survey.
There were 14 respondents covering 15 cars of which 3 were identified as non runners.
Results
* Only 1 member identified that he routinely tests the brakes.
* Several members commented they would only normally test the brakes after carrying out work on them.
* No respondents identified any problems with the valves although one member warned about flexible hoses
protected by plastic coated wire degrading without being obvious.
* Most respondents were aware of how the valves operated but none indicated that they were aware of the symptoms if a valve failed
* One (Australian) member routinely overhauled the G valve each time the master cylinder was replaced or
new seals were fitted
Conclusions
From this relatively small sample it would appear that the issue reported in the LOCI magazine may not be widespread. However, as only one member in this survey routinely tests the brakes and no one was aware of the symptoms of full or partial failure of a valve this may not be a accurate observation.
Recommendation
As the failure of a G valve is unlikely to show up in UK MOT test unless it is causing low or zero pressure to the rear brakes, I would recommend regular moderate braking checks somewhere safe preferably off the public highway. I suggest that the policy of overhauling G valves at the same time as master cylinders is good practice. Please note there is no overhaul kit available as far as I know for the reducing valves used on Mk111 cars and 6 cylinder versions.
I will report these findings to LOCI for incorporation in the next magazine. If you have any further comments, please add them to this thread as soon as possible.
With thanks
David
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Post by Penguin45 on Oct 13, 2013 17:23:49 GMT
Many thanks to David for pulling this information together for us all.
I suspect that all of us should make an effort to check the effectiveness and balance of our brakes on a far more regular basis - I am not the one who does it regularly; I will make a point of it from here on.
For the record, the MkI G valve uses seal kit 8G 8992 or Girling SP2275/2. I have managed to acquire a small stock of these with the help and assistance of Chris Linford, so if you feel the urge to strip and service the valve, please PM me.
Chris.
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Post by indianajones on Oct 15, 2013 19:57:33 GMT
Cheers David,
Sorry for not be able to take part, have been snowed under lately.
I do inspect my brakes every few months, and give them a test, though not heavy braking. I shall make more of an effort to keep a closer eye on them
-Andrew
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Post by tommydp on Oct 15, 2013 20:22:21 GMT
I tested my brakes today, without planning to..
A cat crossed the road, coming out of nowhere in the dark.
I can confirm both the brakes and seatbelt works! The car stopped instantly in a straight line, as far as I could tell the rear ones did not lock. The brakes were fine afterwards too, and no loss of brake fluid:-)
I must say the 1800's braking system is impressive for a 43 yrs old car. It can really measure up with modern cars, and feel even better than some far younger cars' brakes.
Glad the cat was saved, I'm pretty soft when it comes to animals:-)
Regards, Tommy
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Post by indianajones on Oct 15, 2013 20:36:14 GMT
Hmmm Tommy reminds me of a time when I had to brake hard.
The rear locked up, but the car stay straight. Is the system working right? or is the idea to prevent lock up?
-Andrew
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Post by Nick RS on Oct 15, 2013 21:02:55 GMT
Tommy,
You've just put a thought in my head. When I did my emergency brake test I can't remember how the seatbelts reacted. I have reel belts but they don't lock when pulled by hand. They did pass the recent MOT test though.
Nick
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Post by Penguin45 on Oct 15, 2013 23:26:04 GMT
Indy, the G valve should cut off the supply of continued brake pressure to the rear brakes under heavy deceleration; maintaining the applied pressure and diverting the pedal pressure to the front brakes. This means that the rear of the car has braked but rotating wheels to keep it straight, whilst the front brakes actually stop it. It's a 40+ year old system, so it won't be perfect, but the rear wheels shouldn't lock.
Nick, the early inertia reel belts operated on a pendulum ratchet lock. Pulling the belt, even hard, won't lock the reel. The car, again, needs to be decelerating hard for the pendulum to swing and lock the ratchet. I have to remind the MoT tester each year about this, as the "yoof" will say that the belts don't lock.
Chris.
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Post by dave1800 on Oct 16, 2013 1:24:19 GMT
Andrew. The rear wheels should not lock up. BUT if you hit the brakes really hard and fast the pressure to the rear may build up faster than the ball can move and cut off the increase in pressure, overcoming the brake valve design. This is much more likely if you have the rear brake adjustment just one notch too tight and /or the calipers and discs are not 100% requiring greater pressure. You also need to take into account the road conditions, if the rear wheels hit a bump or a slippery patch at the time it may cause lock up. IF in this situation your rear brakes are not properly balanced the car can easily spin as in a hand brake turn. I would suggest when you have time that you repeat the test a couple of times and check it all out. Regards David Hmmm Tommy reminds me of a time when I had to brake hard. The rear locked up, but the car stay straight. Is the system working right? or is the idea to prevent lock up? -Andrew |
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Post by dave1800 on Oct 16, 2013 1:28:07 GMT
Perhaps we should call this the Black Cat Test to go with the Scandinavian Moose/Elk test which I'm sure the 1800 would pass with flying colours unlike a certain Mercedes  Regards David I tested my brakes today, without planning to.. A cat crossed the road, coming out of nowhere in the dark. I can confirm both the brakes and seatbelt works! The car stopped instantly in a straight line, as far as I could tell the rear ones did not lock. The brakes were fine afterwards too, and no loss of brake fluid:-) I must say the 1800's braking system is impressive for a 43 yrs old car. It can really measure up with modern cars, and feel even better than some far younger cars' brakes. Glad the cat was saved, I'm pretty soft when it comes to animals:-) Regards, Tommy |
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Post by dave1800 on Jan 30, 2014 6:14:30 GMT
I recently heard from Tony H who wrote the initial warning in the LOCI magazine. Unfortunately the company he asked about rebuilding the G valves has not yet responded so he is chasing this up. He has now fitted shock absorbers to the front suspension with stronger bump stops and reports that this has transformed the braking and handling on poor surfaces with very little effect on the firmness of the ride. I think his set up is similar to Nick's. The good news is that his replacement G valve functions as intended even with the suspension changes.
David
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Post by andrewa on Jan 30, 2014 16:19:01 GMT
Really useful stuff. By the way did Tony H use std mini shocks or Konis or something else and if adjustable, what settings?
Cheers
Andrew
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Post by dave1800 on Jan 31, 2014 3:04:00 GMT
Hi Andrew This is all I have "Firstly, the Rally Style front suspension mods with external dampers and heavy-duty bump stops represents a HUGE improvement on cross-country roads. The ride is much better controlled, but not seriously harder, and cornering and braking behaviour is vastly better. The damper kit is available from mini spares outlets as a mod for hydrolastic Coopers. One just needs the info from Ken Green to know how to fit the components." There are details of how to fit the front mini type shocks on the Australian eighteenhundred website available for members under "service bulletins". If you haven't already signed up I would strongly recommend you do. regards David Really useful stuff. By the way did Tony H use std mini shocks or Konis or something else and if adjustable, what settings? Cheers Andrew |
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Post by andrewa on Jan 31, 2014 10:36:41 GMT
Thanks - kit's already on the car as you may just be able to see from the photos elsewhere - it was just the standard kit for mini's come with some v.basic shocks - the rally cars had konis and they were adjustable. I'll just wait and see once it's back on the road. Have also had anti-roll bar made up as per the early mk 1's, so with all that and about 100 weight of rust out of the car it should be very different.
Andrew
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Post by dave1800 on Feb 1, 2014 14:06:43 GMT
I'm sure the adjustable Koni's are the way to go to get the set up you desire. I wonder why they removed the rear anti-roll bar quite early in the production. Perhaps it increased the understeer by preventing roll at the rear? David Thanks - kit's already on the car as you may just be able to see from the photos elsewhere - it was just the standard kit for mini's come with some v.basic shocks - the rally cars had konis and they were adjustable. I'll just wait and see once it's back on the road. Have also had anti-roll bar made up as per the early mk 1's, so with all that and about 100 weight of rust out of the car it should be very different. Andrew |
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Post by andrewa on Feb 1, 2014 16:42:12 GMT
Cost probably !
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