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Post by jeff on May 19, 2023 21:48:26 GMT
Hi y'all.
Driving my landcrab I've always noticed a weired feeling with the brakes. The pedal is firm and not spongy.
Never a problem with MOT tests, however, being used to modern braking systems, I notice there isn't much feel. The brakes at relatively low speed, are either on or off, with the occasional lack of release for a second or two.At higher speeds, the progression is satisfactory and very effective.The new master cylinder was fitted last year due to a leak in the old one.
Now, I do admit the remote servo isn't the original Girling unit but a fairly new Lockheed unit, which is of larger diameter and design.
The brakes will stop the car in short order but, hmmmmm I personally don't like the feel and the lack of steady, graduated progression particularly at low speed.
I'm wondering if it's worth installing a rebuilt Girling mk2 unit which I believe was of the type originally fitted.
Would it make a difference to the feel under my foot??
Jeff
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Post by dave1800 on May 20, 2023 0:49:28 GMT
Hi Jeff Have you ever had the "G" valve overhauled, that could possibly be the cause of the symptoms you describe although a non standard servo could also be the culprit. I assume you have already checked the calipers and wheel cylinders etc? The Mk1 brakes were noted for being progressive but it is subjective. David Hi y'all. Driving my landcrab I've always noticed a weired feeling with the brakes. The pedal is firm and not spongy. Never a problem with MOT tests, however, being used to modern braking systems, I notice there isn't much feel. The brakes at relatively low speed, are either on or off, with the occasional lack of release for a second or two.At higher speeds, the progression is satisfactory and very effective.The new master cylinder was fitted last year due to a leak in the old one. Now, I do admit the remote servo isn't the original Girling unit but a fairly new Lockheed unit, which is of larger diameter and design. The brakes will stop the car in short order but, hmmmmm I personally don't like the feel and the lack of steady, graduated progression particularly at low speed. I'm wondering if it's worth installing a rebuilt Girling mk2 unit which I believe was of the type originally fitted. Would it make a difference to the feel under my foot?? Jeff |
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Post by andrewa on May 20, 2023 5:56:17 GMT
Take your pick from these!
I had problems with aftermarket servos but not feel related just not working. And then one of the replacements did work and worked forever! Just luck of the draw.
The only similar ish problem I had was it felt like the brakes were slow to release. Worse when you really stood on them. Couldn’t figure it out then when doing an auto test I braked extremely hard and car locked up and wouldn’t release but 10 mins later all was fine!
As Dave was suggesting, that turned out to be the G valve which had been plumbed in the wrong way round…easy mistake to make apparently.
Good luck
Andrew
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Post by jeff on May 20, 2023 9:40:40 GMT
Thank for the info lads.
I've never had the G valve out, and as far as I know, it's never been overhauled. However all the pipework has been replaced, either by me or PO's.
I've read somewhere that the "one size fits all" Lockheed servo does have a propensity to hang, but I've only experienced it under light braking.
I will have a look in the books and check the G valve plumbing.
The front calipers are both new, and rear wheel cylinders seem in good order.
Any thoughts on the Girling mk1 and mk2b servos? Quite expensive reconditioned I believe. I'd happily have a go at reconditioning one if I found a suitable unit.
Lots of seals.
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Post by andrewa on May 20, 2023 13:58:28 GMT
My G valve issues started after a marque specialist had redone all the plumbing!
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Post by jeff on May 20, 2023 14:55:34 GMT
Luckily, the PO, had this problem and fitted a switched tell-tale warning lamp in the dash. When the brakes are applied the red light comes on with the stop lamps. It stays on if the brakes hang.
I did wonder if it was the master cylinder causing the problem so I fitted a new one last year.
I've stripped and cleaned the air valve on the servo in case the small piston was sticking..I also remember someone in the dim and distant, suggesting to remove one of the two O ring seals on the air valve to reduce drag in its movement. I can't remember if this servo has one or two seals.
I now turn off the tell-tale lamp as I find it a distraction and if I don't see it I don't worry about it.
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Post by dave1800 on May 21, 2023 0:03:37 GMT
I think it would be more difficult to put the MK1 valve in upside down as it is quite different in shape and operation and I think it would make the system difficult to bleed, but who knows! David My G valve issues started after a marque specialist had redone all the plumbing! |
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Post by jeff on May 21, 2023 17:28:04 GMT
Yes Dave, agreed.
I think I'll wait until an original used servo crops up. Im pretty sure that will put it back to how it should be.
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bandit1
Member
Posts: 34 
Attribute: Technical Expert
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Post by bandit1 on May 23, 2023 7:49:45 GMT
Ive never really found what I would describe as a "Good" footbrake on any of my past Landcrabs, and talking to many other owners they seem to have the same too !
Wooden feeling and brakes either sticking on and slow to release is a bit of a problem even when the cars were new.
Hit em hard n they can Lock on tight sometimes !!
I know we shouldn"t compare with modern cars but my 107 Peugeot has a 9" servo and a touch of the pedal is all thats needed with a good progressive feel !
I understand our cars are a heavy old thing but they really should have a better system ??
Chris.
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Post by dave1800 on May 23, 2023 11:09:10 GMT
Hi Chris Has your experience been the same with Mk111 cars that don't have a G valve but a simple pressure reducing valve in the rear brake line? It would be interesting to hear comments from anyone is Australia with the PBR brakes. I suspect that the ball in the G valve may be the culprit if it gets gummed up. I didn't notice this problem with crabs when they were new but my experience with other cars for comparison then was somewhat limited. David Ive never really found what I would describe as a "Good" footbrake on any of my past Landcrabs, and talking to many other owners they seem to have the same too !
Wooden feeling and brakes either sticking on and slow to release is a bit of a problem even when the cars were new.
Hit em hard n they can Lock on tight sometimes !!
I know we shouldn"t compare with modern cars but my 107 Peugeot has a 9" servo and a touch of the pedal is all thats needed with a good progressive feel !
I understand our cars are a heavy old thing but they really should have a better system ??
Chris. |
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Post by jeff on May 23, 2023 14:43:08 GMT
Well, here's interesting.
I took her for a jog today and switched on the tell tale lamp, which works with the brake lights.
I wanted to monitor it more closely and found the following:
With the car stationary and engine idling, I applied firm pressure on the brakes and they release immediately, the tell tale lamp goes off and the car is free to roll.
However it's when the brakes are applied on the overrun at low speed with throttle closed that they hang for a few seconds before releasing.
I just wondered if the increased vacuum in the inlet manifold has anything to do with it. Maybe a valve being pulled tighter??
Any thoughts?
Jeffm
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Post by dave1800 on May 24, 2023 0:46:50 GMT
Interesting. It could be the effect of the higher vacuum on the servo or it could be the G valve ball sticking. I guess the majority of the G valves have never been overhauled since the cars were made? If you could repeat the test safely with the car in reverse then this may help point you in the right direction (sorry pun not intended!) David Well, here's interesting. I took her for a jog today and switched on the tell tale lamp, which works with the brake lights. I wanted to monitor it more closely and found the following: With the car stationary and engine idling, I applied firm pressure on the brakes and they release immediately, the tell tale lamp goes off and the car is free to roll. However it's when the brakes are applied on the overrun at low speed with throttle closed that they hang for a few seconds before releasing. I just wondered if the increased vacuum in the inlet manifold has anything to do with it. Maybe a valve being pulled tighter?? Any thoughts? Jeffm |
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Post by jeff on May 24, 2023 12:28:37 GMT
Thanks David I will check that one out over the weekend.
Jeff.
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Post by dave1800 on Jun 10, 2023 0:19:13 GMT
There is an article in the June 2023 LOCI magazine that fully resolves the wooden or non progressive brake action some have noted. David Ive never really found what I would describe as a "Good" footbrake on any of my past Landcrabs, and talking to many other owners they seem to have the same too !
Wooden feeling and brakes either sticking on and slow to release is a bit of a problem even when the cars were new.
Hit em hard n they can Lock on tight sometimes !!
I know we shouldn"t compare with modern cars but my 107 Peugeot has a 9" servo and a touch of the pedal is all thats needed with a good progressive feel !
I understand our cars are a heavy old thing but they really should have a better system ??
Chris. |
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Post by 1800heap on Jun 10, 2023 7:49:52 GMT
Hi all
I can tell you that with the Australian Mk2 I hated the feel of the brakes! It has a dual circuit PBR setup. They didn't work very well and the feel was nasty. Having said that I have not and had not inspected them for problems. It could well have just been poor maintenance. OKR on the other hand, a MK3 with the 3 pot S setup and bigger disks, I always found to be excellent. Good feel and worked well. Some fade if you really got into it, but that was not unexpected and took a couple of good hard stops from high speed. I have to say that I prefer a slightly heavier feel. I hate my wifes Toyota Corolla, you touch the brakes with that and it stops like you just jumped on them too hard. Now after driving it for a while and getting used to it, the progression is fine all be it very light in touch. Anyway never has any issues with OKR, although slight concern at the single circuit!
Nick
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