minibreakdown
6 posts
Joined: 07/07/2010 14:40:51
Location: Autevielle France
brake limiter valve/brake regulator adjustable valve
Hello all I have a 1989 998 mini flame that has just failed its French MOT for the rear brakes only have 20kg of pressure on each side. The front brakes work fine.
I have just returned from the garage where he has said it is a problem with the brake limiter valve FAM7821 and needs a new one but suggested a good idea would be to fit a brake regulator adjustable valve MS72.
I asked if the adjustable valve replaced the brake limiter or was fitted into the braking system and the both worked together. He said it would replace the brake limiter but I needed to find an adjustable that has the correct brake pipe connections as the limiter after showing him a picture of MS72 on line at the garage.
I have researched the forum and the technical manuals to see how these parts work together or not!!!
This may be a case of lost in translation between me and the mechanic.
Could anybody please let me know should I replace like for like (FAM7821) or try and fit an adjustable brake regulator? If it is fit the adjustable, what parts do I need and where does it go in the system?
Posted: Jun 26, 2014 12:39 PM
Tim
1849 posts
Joined: 18/10/2004 09:40:59
Location: Bournemouth United Kingdom (Excluding channel Islands)
If I remember correctly, that brake limiter (FAM7821) is mounted on the bulkhead and has two pipes going in from the master cylinder (because it's a dual line system) and two pipes going out - one to the front brakes and one to the rear.
The simplest thing would be to replace it like-for-like, but it's not cheap.
If you decided to fit the adjustable (MS72), then that works on the rear brakes only and is fitted on the rear subframe, where you would normally see a simple 3-way union. You would have to get rid of the brake limiter on the bulkhead, and join the two sets of pipes somehow.
Personally, I don't like limiters of any sort and on my 63 Cooper I disabled the limiter on the rear subframe by removing the insides, so it just acts like a 3-way union. I haven't had a problem with the rear brakes locking up, except on very wet or loose surfaces.
If it was my car, I would try and do the same and disable the limiter on the bulkhead. I don't know if it's possible to take it apart and put it back together again without leakage, but it's worth a try. Failing that, you can just remove it and replace it with two female-to-female connectors.
Posted: Jun 26, 2014 08:44 PM
Thanks for the comprehensive reply Tim and I now understand it a lot better.
I think that I will be replacing the brake limiter like for like and not add the adjustable onto the braking system or removing the limiter completely. Reasons for this are my son drives the car and he hasn't got the driving experience if the rear brakes locked up and I don't want some dodgy mechanic in rural France messing about with the brakes too much. Also I would like to keep the car pretty standard.
Once again thanks for the info
Posted: Jun 27, 2014 07:22 AM
OK. As per my previous post I bought a new brake limiter (FAM7821) from this fine online shop. Had it fitted at the garage and I went to pick it up this morning. To be told that the problem still exists and the rear brakes are still only getting 20kg of pressure which is exactly the same as before. I now have a spare brake limiter should the new one ever fail. I asked it it could just simply be a partly block pipe from the limiter to the rears but he doesn't think it is as he gets a good flow of brake at the rear brakes.
To pass the MOT for the rear brakes, on the rolling road test, he has suggested loading up the boot and back seat with 3 or 4 sacks of cement to see if this extra weight will increase the force on the rear wheels somehow.
If this does work, great. But in anticipation of a spectacular still only 20kg and another fail would anybody have any ideas what the problem could be? The system seems quite simple.
Tim I am seriously taking up your earlier suggestion of removing the brake limiter altogether or as the French mechanic suggested, swap over the rear and front brake outlets for the MOT then change them back after. That would make for a fun drive there and back! Would rather do things properly though.
Thanks in advance.
Posted: Jul 10, 2014 12:50 PM
I'm afraid I don't really understand what 20kg of pressure means, or whether adding extra weight to the rear of the car would make any difference to it.
One thing that you need to establish is: does the handbrake work properly? I ask this to establish if you're certain that the brake shoes themselves are OK - quite often on the rear brakes you'll find that a leaking cylinder has smeared brake fluid all over the shoes and no amount of brake pressure will make them work effectively.
On my mini, the handbrake will lock the rear wheels solid when going down my (fairly steep) driveway on a damp morning.
It's difficult if you have to rely on a garage doing all the work - especially if they don't really know what they're doing!
Posted: Jul 10, 2014 01:50 PM
Thanks again for the reply again Tim. I will try the hand brake out to see what happens.
Both rear wheel brake cylinders were replaced some 2 - 3 years ago so are hopefully OK.
I don't understand the 20 kg pressure either. I know that to test the pressure they took out the bleed nipple and screwed on a pressure gauge and then pushed the pedal, showing how much pressure in Kg's is getting to the rear brakes. One thing for me is that both sides have the same amount of pressure so I would have thought it would have been the limiter.
I'll go and try the hand brake this afternoon and see what happens.
Posted: Jul 11, 2014 12:59 PM
Interesting - I've never heard of measuring brake performance like that! Maybe something's got lost in translation, but pressure would have to be measured in kg's per square something, not just kg's. Did they tell what reading they got on the front?
Posted: Jul 11, 2014 01:35 PM
No they didn't. I don't know if they even tested the front!
Just been out in the car and on a hill near me the rear nearside locked up when the hand brake was applied. tried this several times with the same result so it looks like I'll be taking the nearside apart this weekend to see whats going on.
This is why I like forums as the amount of advice and knowledge is invaluable, especially when you live in rural France. It does make me wonder why the garage didn't think to try that. Thanks again Tim.
Posted: Jul 11, 2014 03:35 PM
Update for what it's worth.
The problem with only one wheel locking up with the hand brake was sorted by properly adjusting it.
The rear brakes. On both sides one of the pistons on each of the cylinders was binding but not leaking fluid until my son pushed the brake pedal, I stopped the shoe that was working from moving by applying pressure to it. Brake fluid then poured out from the other piston but still didn't move and remained stuck solid. 2 new cylinders about to be ordered.
When fitted and both of the brake shoes will be applying pressure to the drum instead of just the one then the 20 kg of pressure should hopefully be the right amount to get the correct braking force. Why the garage couldn't have worked it out I don't know.
I suppose now I have a spare brake limiter if anyone is around the Pyrenees Atlantique area of France and is in need of one, contact me.
Posted: Jul 12, 2014 04:10 PM
miniDave
9 posts
Joined: 17/09/2007 00:13:13
Location: Lisarow, NSW Australia
Main Topics >> VALVE CLEARANCES ??? >> VALVE CLEARANCES ???
The gap mentioned seems right according to the book, however my tuner always sets pushrod operated clearances as 0.008 inlet and 0.010 on the exhaust.
Cheers
Posted: Dec 29, 2009 11:53 AM
woodruff
29 posts
Joined: 18/02/2007 17:02:36
Location: Rome Italy
VALVE CLEARANCES ???
Errr...Thats too tight and can lead valves and their seats to further damage.
12 thou inlets and 14 thou exhauts is OK, especially for a standard 1275 cam/rockers. On a Mg metro engine set 14thou inlets and 16 thou exhausts WITH ENGINE COLD. Then warm up engine and recheck, espacially when using old rockers/pushrods.
Posted: Dec 29, 2009 03:04 PM
CrAzYSteve
5 posts
Joined: 25/01/2008 11:38:21
Location: Cambridge United Kingdom (Excluding channel Islands)
HEATER VALVE ORIGINAL ANGLED TYPE ON CYLINDER HEAD
Hello,
I have just upgraded my 998cc to a 1275GT engine, all looks the same and fits with no issues in the car, the issue i have being new to the mini world is the heater, i have noticed that where the Original heater valve fits on the cylinder head its all block in. Does the 1275GT engine have another way of heating the car. Im lost lol
Hope you can help
Steve
Posted: Apr 06, 2010 03:09 PM
Kevin
20 posts
Joined: 21/03/2010 21:57:14
Location: ballinteer Ireland (S.)
valve clearence specs
hello mini lovers,i have a 1275 a series engine.the dude i bough it from says i has a high lift cam shaft.just wondering if the specs in the haynes manual are ok for this set up?also,does anyone know how i can identify the type of rockers being used?
all replies aprieciated,Kevin
Posted: Sep 15, 2010 11:09 PM
Scott Jones
2 posts
Joined: 16/02/2011 09:24:15
Location: Huntingdon United Kingdom (Excluding channel Islands)
Rocker cover valve?
Hey i bought my austin mini last night, i picked it up from luton on planned on driving it home to cambridge.
After getting halfway home there was a loud rattling/ticking noise coming from the engine bay so i pulled over and as soon as i put my foot on the clutch then engine died.
I called my breakdown cover and the guy told me it sounds like its the 'rocker cover valve' either broken or loose.
is this an easy fix? and does it sound like its the problem?
Cheers Scott
Posted: Feb 16, 2011 09:27 AM
It sounds like you may have a broken or stuck valve. You'll need to get under the bonnet and have a look round. First thing, take the plugs out and see if you can turn the engine over on the starter motor. It should blow petrol/air out of each plug hole. See if you can see the pistons moving up and down inside the bores as well. Then take the rocker cover off and watch the arms move up and down as the engine turns. If there's any nasty noises whilst doing this, then you've got a problem.
Since your original posting was invisible to the forum, I know from experience that if you reply to this posting, your reply will be invisible as well. Email me at tim_roberts65'at'hotmail.com (replace the 'at' with the usual symbol) and I'll post your replies for you.
Posted: Feb 16, 2011 03:54 PM
Mike Z
12 posts
Joined: 29/08/2010 04:59:59
Location: Richmond Bc Canada
Valve Rocker Adjustment
Someone please help me with adjusting the valve rockers on my Mini 1.3 SPI.
Do I need to turn the engine twice? If so, which numbers can be adjusted on top, dead-center? And which numbers on the second turn?
Thank you for any input.
Posted: May 25, 2013 03:37 AM
Barry Brown
511 posts
Joined: 23/06/2008 12:08:31
Location: New Barn United Kingdom (Excluding channel Islands)
Hi, Take the spark plugs out to make it easier to turn and put the car in 1st gear but leave the keys out of the ignition.
Now use the "Rule of 9" for a 4cyl engine. When tappet 1 is down then 8 will be up. (1+8=9) When tappet 3 goes down then 6 will be up (3+6=9) and so on. Tappets are numbered from the thermostat across to the water valve 1-8. Ideally try to get hold of a 'ClikAdjust' tool that gives 1 click per 'thou' of adjustment. These are better than feeler gauges as they take into account any wear on the rocker arm face that might otherwise be bridged by the feeler gauge thereby giving a false, and tighter, tappet clearance when measured. Once done nip the nuts tight and refit the plugs and rocker cover and give it a test.
Posted: May 27, 2013 08:32 PM
Thanks Barry. I guess I need to pull the starter out to get good access to the flywheel. I have autotransmission. Are you familiar with 1-turn engine? How many valve rockers can be adjusted? If not, should I turn the engine 8 times, 360 degree turn?
Posted: May 28, 2013 04:08 AM
Hi, I've never heard of 1-turn i'm afraid. As you may have also guessed I've never had to do it on an automatic either. Some minis can be cranked over using the fan belt once the spark plugs are removed. The alternative is to get a socket/spanner on the crank pulley nut rather than take the starter motor out.
Posted: May 28, 2013 04:20 PM
Thanks Barry. I appreciate your help. Your advice was very helpful. All adjusted now according to what you said.
Posted: May 31, 2013 05:28 AM