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Post by harvey on Feb 15, 2007 16:50:04 GMT
All cars with handbrakes working on the front discs have one major flaw which can cause serious problems, and that is the hand brake not holding and the car rolling away. As the front discs get more work to do than the rear they get hotter, you give the brakes a workout and then park on a hill leaving the handbrake on, the discs contract and the car rolls away.I've picked up the pieces on quite a few occasions.
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Post by Deleted on Feb 15, 2007 22:29:31 GMT
'Tis true, but as more modern cars have rear discs nowadays, it can still cause problems :- as an ex-Jaguar X-type owner, I can testify to this A recall (but only for manual transmission cars ) was made in 2003/2004. Now, Rover content:- has anyone got access to a brake x-reference book (Lockheed or Girling) that may show the different master cylinders for P5 and P5 B's? one from the mid 70's would be ideal.
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Post by Phil Nottingham on Feb 15, 2007 22:34:55 GMT
The master cylinders are different on P5's to P5B's and two types were actually used for the P5B one with a CI body and one with alloy.
Why do you want to know the part numbers?
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Post by Deleted on Feb 23, 2007 10:37:29 GMT
Sorry so long replying Phil et all, reason for wanting the part numbers is to see if there was more than one P5B /V8/ post 67 master cylinder part number. If there isn't, there should be as I got to check the '73 Coupe and it has DEFINITELY got a differnt braking system, unfortunately my photos are rubbish (lighting) and I had to examine it whilst wearing my suit (it's on grass and filthy:- the car as well! ;D ) but there are two reservoirs, and a very different pipe set up. it looks as though the M/C is single circuit (but different to my 71 V8) but supplies the servo which then supplies two circuits. Anyone else with a late model that could have a look at theirs to see what they've got? I'm just interested now! Can't add the image!
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Post by Phil Nottingham on Feb 23, 2007 17:19:29 GMT
It sounds like a special system - mines a late model and I know of even later ones with the same set up as standard.
???The servo on the standard one supplies three circuits in effect via the "T" junction i to osf one n/f and one to the rears.
Still not sure what you mean - have pipes been modified somehow when replacing corroded ones?
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Post by Deleted on Feb 23, 2007 17:33:09 GMT
Seems an awful lot of messing about for a one off order, it's quite an intricate setup on a car that was going out of production soon. No-one else got two hydraulic reservoirs under their bonnet? (Of their V8, I know manual P5's have ) I wonder if export regs were the reason. Any ex-BL people in the club that may be able to throw some light on it? PS Can anyone give me the heads up on adding images?
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Post by Phil Nottingham on Feb 23, 2007 19:52:58 GMT
Whilst I think you may have something re special export fit - such cars were no different to special customers orders eg the Miinistry or even influential private customers. Some cars may be have done for development purposes or a nervous owner. Rover always did these little specail things, the P5 especially towards the end of production was virtually handbuilt by a small dedicated team. The bodies and subframes and virtually every other major component were subcontracted outside anyway. I have seen at least two cars with the handbrake on the left (with RH steering) and special paint jobs/ sundym/ aircon were not uncommon Whilst I have not seen your set up it does not seem such a bother although I can see no real reason for it. Have you any PO history?
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Post by Warwick (Ozcoupe) on May 1, 2007 1:38:30 GMT
An interesting thread. Single-circuit braking is something that bothers me about old cars too and I've been contemplating the possibilities.
It seems to me that it should be possible to find a suitable master cylinder. There are several things that have to be considered.
It would need to be from a car that had drums on the rear and discs on the front (like the P5B) because that will generally mean the booster is not part of the master cylinder.
Therefore we're looking at the late 60s or early 70s. (Again, like the P5B).
It would need to have a bore chosen to retain the same or similar hydraulic "gearing" or mechanical advantage. If the diameter remained the same then the stroke would be shorter because, in effect, each of the tandem pistons would only be displacing fluid into half of the original circuit. Furthermore, it won't be an equal "half" from a fluid volume point of view. Calculating it will be an interesting exercise.
Remote reservoirs would help, but it could probably be modified if the originals won't fit in the space available.
Then of course, you have the engineering/insurance issues. It would undoubtedly make the car safer, but only if it was done competently - not to mention legally.
I have a new PBR (Repco) master cylinder from an early Aust. Ford Falcon somewhere in the shed. It's intended for my Bolwell which has disc/drum brakes and a separate booster for the discs. I'll see if I can find it next weekend and check the dimensions.
Whoops! Just got home, found the PBR master cylinder, and had a closer look at the Rover. Discovered that the booster feeds both the front and rear brakes......as you all knew, of course. It's the first car of this age that I recall having the drums boosted too. One of the few advantages of drum brakes is that they are self-energizing, so to speak, due to the way the shoes contact the drum. Does the P5 have trailing shoes? Seems odd to me. Anyway, this will need a re-think and I'm not about to change anything yet. The PBR cylinder would come close to fitting in the same spot if the windscreen washer bottle was moved although the rear reservoir may foul the handbrake cable and the bore might be bigger. Another task for another day.
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Post by johnwp5bcoupe on May 1, 2007 5:22:00 GMT
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Post by Phil Nottingham on May 1, 2007 18:20:19 GMT
The braking system is a standard UK version for many years, with or without Servo. The rear shoes are one leading one trailing which coupled with the front disks gves the right braking effort balance without the various balancing valves some cars require. Maintained properly its entirely safe as the handbrake should be able to stop the car within a reasonable distance - if its does not something is wrong somewhere.
The main problem is these days it the fit and forget attitude for all modern goods and cars are no exception that no longer requires giving regular attention both as to time span and miles as such things on old cars will sieze up or deteriorate through lack of use
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Post by Warwick (Ozcoupe) on May 2, 2007 0:38:22 GMT
Thanks Phil. All the local cars that I'm familiar with from that period had one leading and one trailling too (easiest to make) but didn't boost them. Discs of course need boosting since there is no self-applying effect and the friction area is so small.
I guess you're right about being safe, and I've never had brakes fail on a car although most early Holdens would display bad fade if you didn't use them carefully in the mountains. My car isn't going to be in daily use, but it will get used often, I hope. Its role will be as the spare car as well as the hobby car.
I need to fix the fluid level float too. I've removed it and replaced it with the cap off a can of paint stripper (same thread) in order to keep the air out. The original cap that retains the float assembly has all but corroded away and the float just sits in the open top. Not good.
I also need to get to know the car a bit better and see how it behaves under hard braking and when only using the hand brake. I haven't driven a car this old for a very long time, except for various Peugeots and they are much lighter and over-braked by comparison.
It goes in for its RWC tomorrow (MOT) and I should get my new set of replica 60s plates next week, so it can be registered in Victoria again.
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Post by Deleted on Jul 1, 2007 14:58:09 GMT
Having read everything posted on the subject of brakes, I had the whole braking system replaced except the pedal and braking is still no better than it was initially,that is to say mediocre.However, a P5B was not desigened to be driven like a MK 2 Jaguar so I can live with what I have got.
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Post by MK IA Norway Viking on Apr 28, 2022 19:04:30 GMT
Whilst the brakes will not be adequate for a 5.1L powerplant they should be more than adequate and not too high a pedal effort. A firm shove should lock the wheels. In my view they are fully up to modern standards and not as spongy as some. I think you need to recheck the system carefully Your linings & pads may not be bedded in? Rear cylinders not floating Oval rear drums duff servo - I have never had much long term success with rebuiltones Air leaks on servo vac pipes/tank? faulty one way valve on manifold collapsed/ballooning flexis restricted damaged bundy tubes I have found this old thread from 2007, for the issues described therein match my newly developed problem. My MK IA has been in lay up for a year pending camshaft replacement +++ to delete a very annoying rattle from the valves. I've also replaced the ower steering with a newly overhauled unit, due to leakage of hydraulic oil. The servo is of a newer type, is about 6-7 years old and has worked very well in the past. With the engine back in operation the brakes have developed a very peculiar behaviour - the braking effect is very poor. I have to apply much harder pressure to the pedal than I used to in the past. To an extent where safe driving requires careful planning and observation on the traffic ahead. No leakages and seemingly no false air anywhere - I have not yet checked the pads for glazing, for it feels as if there is oil on the discs, wthat's how poor the braking effect is. I seriously doubt any oil on the discs, it is merely a way to describe the reduced braking effect. I have taken the car for a 100 mile run, to see if the problem would cure itself with the car being back on the road. Alas, no improvements. Any suggestions from the eminent Club Members on where the fault may lie ? Greetz from MK IA Viking from Norway !
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Post by Phil Nottingham on Apr 28, 2022 19:31:58 GMT
The servo seems to be sticking. With engine off press the pedal down hard and start the engine. The pedal should move down. If it does not press and release VERY hard several times with engine running and the repeat the first stage.
If no change check that after turning off the engine disconnect the vacuum at the servo without its non-return valve which may be in the the servo body hose connection - so just pull the whole assembly out of its rubber grommet or somewhere in the vacuum hose. This will show whether there is any vacuum in the servo as there should be for several minutes after turning off the engine
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Post by MK IA Norway Viking on Apr 29, 2022 12:16:16 GMT
Thank you, Phil, for this very useful advice.
I will do as you suggest, and report.
Kindest regards, Christopher
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Post by MK IA Norway Viking on May 1, 2022 23:05:33 GMT
Whilst the brakes will not be adequate for a 5.1L powerplant they should be more than adequate and not too high a pedal effort. A firm shove should lock the wheels. In my view they are fully up to modern standards and not as spongy as some. I think you need to recheck the system carefully Your linings & pads may not be bedded in? Rear cylinders not floating Oval rear drums duff servo - I have never had much long term success with rebuiltones Air leaks on servo vac pipes/tank? faulty one way valve on manifold collapsed/ballooning flexis restricted damaged bundy tubes I have found this old thread from 2007, for the issues described therein match my newly developed problem. My MK IA has been in lay up for a year pending camshaft replacement +++ to delete a very annoying rattle from the valves. I've also replaced the ower steering with a newly overhauled unit, due to leakage of hydraulic oil. The servo is of a newer type, is about 6-7 years old and has worked very well in the past. With the engine back in operation the brakes have developed a very peculiar behaviour - the braking effect is very poor. I have to apply much harder pressure to the pedal than I used to in the past. To an extent where safe driving requires careful planning and observation on the traffic ahead. No leakages and seemingly no false air anywhere - I have not yet checked the pads for glazing, for it feels as if there is oil on the discs, wthat's how poor the braking effect is. I seriously doubt any oil on the discs, it is merely a way to describe the reduced braking effect. I have taken the car for a 100 mile run, to see if the problem would cure itself with the car being back on the road. Alas, no improvements. Any suggestions from the eminent Club Members on where the fault may lie ? Greetz from MK IA Viking from Norway !
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Post by MK IA Norway Viking on May 1, 2022 23:13:45 GMT
Thank you, Phil, for the excellent tips and recommendations for braking issues on my 1962 MK IA.
I have stepped hard on the brake and then started the engine, in an effort to release a (possibly) sticking piston. No difference. I can feel, actually, a slight back-pressure on the brake pedal when catching up with slower traffic, suggesting the vacuum-operated piston is indeed moving, for as it moves it will act on the control-piston which in turn alters the pressure on the braking fluid.
Next step will be to run the engine and then disconnect the hose from manifold to servo unit, to verify the presence of vacuum.
I shall report on same soon.
Another issue I have is that the left rear brake drum turn with resistance due to sticking brake pads. When I use the parking brake they will not release fully.
By turning the adjuster on the backplate the pads ease up rendering the drum to rotate freely.
I tried to undo the 2-3 screws holding the drum in place however they are stuck hard. I did not put much force on them for fear that I may ruin the screw head.
Are there any useful tip or advice / recommendation on how to make these screws open, so I can get the drum off to inspect hte internals and lubricate where / as necessary ?
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Post by Phil Nottingham on May 2, 2022 12:21:09 GMT
The rear cylinders will no longer be floating and need unseizing. The screws are best removed with a wide blade impact driver and are a consumable item available from Land Rover specialist for a small sum
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Post by MK IA Norway Viking on May 2, 2022 13:58:11 GMT
Hello Phil - so, basically to force them open and secure the drum with new screws, right ?
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Post by MK IA Norway Viking on May 2, 2022 13:59:38 GMT
Worst case scenario will be to use a drill and "remove them", without damaging the thread ... for they are really very very stuck !
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Post by Phil Nottingham on May 2, 2022 14:41:20 GMT
Worst case scenario will be to use a drill and "remove them", without damaging the thread ... for they are really very very stuck ! I have always got them out with an impact driver. Try heating them? Drilling out is a last resort - they are 3/8" BSW
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Post by MK IA Norway Viking on Jun 22, 2022 7:02:37 GMT
The servo seems to be sticking. With engine off press the pedal down hard and start the engine. The pedal should move down. If it does not press and release VERY hard several times with engine running and the repeat the first stage. If no change check that after turning off the engine disconnect the vacuum at the servo without its non-return valve which may be in the the servo body hose connection - so just pull the whole assembly out of its rubber grommet or somewhere in the vacuum hose. This will show whether there is any vacuum in the servo as there should be for several minutes after turning off the engine I have now had my MK IA 1962 on the road after successful MOT, in spite of efficient braking requiring a very heavy effort on the pedal. The fault-finding methods suggested earlier to rectify defects did not have any effect. Having used the car for some time I am happy to advise that the brakes now operate as they should. With the long period off the road the brake pads must have hardened. With use the glazed surface has been worn off, which supports my principal view that the Rover has to be used. A garage queen/repairs "in progress" will decay the vehicle much faster than one in use.
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Post by enigmas on Jun 22, 2022 9:34:34 GMT
If properly maintained the Rover P5 brakes are efficient whether 6 cyl or V8. Sometimes though after market speciality parts are better. Here's some more tech to consider.
P5s have non vented discs...so they both discs need to be a 1/2" thick as per Factory. Any thinner and they'll fade and smoke. If thinner on one side the car will smoke and pull to that side.
Hydraulic hoses. Replace with either new versions of same or stainless braided hydraulic lines. Forget NOS, these are ancient parts fit for the bin. Any professional brake shop can fabricate new hoses. Braided lines don't expand under pressure like the rubber hose equivalent, which believe it or not, if old, constrict the flow of fluid.
Disc Brake Tech (Old Solid V New Vented) Solid discs as fitted to P5s require hard sintered brake pads. Solid discs run hot and this is what they require. No matter what the brake shop gurus tell you, the best pads available are the OEM Factory sintered asbestos ones. If you have a set, guard them like gold.
I've had several brake pads made up in softer non-sintered material. Unfortunately, they functioned pathetically. The softer material illustrated poor brake retardation and also pad crush. This last effect was quite surprising and obviously hindered braking, as hydraulic pressure merely compressed the pad material rather than increasing the pads grip on the disc.
Front Discs The discs should have minimal runout (check with a dial indicator), no more than .003" otherwise the pads are knocked back into the cailpers by disc oscillation. The disc runout can be trued by fitting shim material behind the mounting flange on the studs. Believe it or not, computer printer paper (approx .005) can be fitted behind a couple of securing studs between the disc and hub to rectify the issue. Check again using a dial gauge. The paper shim will crush down under securing pressure.
Discs shouldn't be smooth faced either, give them some tooth with 120 grit sandpaper. This is not a surfacing process if the disc is scored. If scored, send them to a brake shop and have them machine off the absolute minimum amount of surface material. Both discs must be the exact same thickness after machining, otherwise the car will brake erratically.
Brake Booster. Fit a decent booster, preferably new and with at least the same output pressure as the Factory version when new. There's no negative reason on a well maintained system to pick a booster of slightly higher capacity. Disc brakes either vented or solid do not self energize, so require a booster. This is the reason modern cars require so little pressure on the brake pedal.
Rear Brakes. Phil can chime in here. The rear brake linings should "float" and "self-centre". The rear drums should obviously be round and not bell-mouthed or grooved. Nor should the linings be oil soaked from a leaking differential seal. Spraying brake cleaner on oil soaked linings doesn't fix the issue. Rear linings are generally softer material and absorb the oil.
Hope this assists. 😎
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Post by Phil Nottingham on Jun 22, 2022 13:13:11 GMT
I could not agree more!
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Post by lagain on Jun 28, 2022 19:17:55 GMT
I also agree. When my parents were alive and we used to do a lot of shows, we would set off and my father would say 'have you been fiddling with the brakes again ?' Generally the answer would be yes, as I have a bit of a thing about brakes, well, I suppose they are quite important. Last winter I replaced the old Goodridge hoses with new ones, replaced every rubber seal and used new front pads from stock. Offhand I cannot remember what brand they are, but I bought them at Beaulieu autojumble many years ago and they have bits in them. The result of all the work is that she stops amazingly.
If your car does not stop well my first suggestion would be air in the system. When you are on the road and try a test stop keep re-applying the brakes, if the pedal then works from higher up there is air. There should be little free play in well set up brakes. Garages will not spend the required time on them and the best way of doing it is to use the car for a while and then re-bleed.
When I was at agricultural college in the 70s we were told that when a pig is slaughtered the entire pig is used except one thing - the squeal. Apparently this was wrong as the squeal was sent to British leyland to use in their brakes.
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