Toad Brakes Locking Up

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DaveRB55

Well-known member
Joined
May 19, 2017
Posts
45
Hello,
We are on our virgin shakedown trip and have run into a problem.  Have the M&G brake system installed in our CRV.  Came over a hill with a redlight that turned and had to make a somewhat quick stop.  Yes, smelled some brakes /rubber and heard some screeching which was surprising as I did not feel it was that extreme a stop. Drove my car into town a day later and felt thumping as I got up to speed.  Left front tire had a flat spot and rubber ground down.  Had M&G installed at Athens TX factory.  Can?t understand why just one tire locked up and not both.  Having brakes checked this morning on CRV but don?t expect anything as car was braking fine.  Have contacted M&G who says they can reduce air pressure but again problem should be with both tires.  Anyone heard of anything like this.  ABS does not engage when towing.
 
It's not unusual for one wheel to lock up before the others in extreme braking. Simple variations in the brake adjustment and condition can lead to that.  The question is, "Is the M&G applying too much braking to the toad, to the point where a lock-up can occur?"

I would get the CRV brakes adjusted so that each wheel is as close as possible to the others in terms of lock-up adjustment, and then get the M&G braking action turned down a bit to stay well short of any lock-up.
 
Thanks Gary for the quick reply.  I?m headed to the shop to have the brakes checked.  I wasn?t aware brakes could be adjusted for equality in lock up and will follow that up.  m&g said they will help me to  adjust down the pressure...pretty expensive way to verify things are working!
 
That car should have anti lock brakes on it. I'd be inquiring how the brake system you had installed could lock just one wheel. Something doesn't sound right to me.
 
M&G is a system I've had for 18 years and nary a problem,, installed myself on two different vehicles. Presently on a Jeep Liberty.>>>Dan
 
We had the M&G system on both our DPs with a Tracker, a Jeep Grand Cherokee, and an Acura MDX.  When you press the brake in the motorhome, all four toad brakes should engage evenly.  I remember when we got the Tracker hooked up we did a test where we drove both ways in a circle on gravel to test that all four brakes were working together.  Jerry and I talked about it and he thinks it is a problem with the CRV because, if it was the M&G system, all four toad wheel brakes would be locking, not just one.

ArdraF
 
I think Ardra has it on the head,, the M&G system applies pressure at the master cylinder of the toad,, after that the braking system acts just like it would if you pressed the brake pedal with your foot.>>>Dan
 
That car should have anti lock brakes on it. I'd be inquiring how the brake system you had installed could lock just one wheel. Something doesn't sound right to me.
Click to expand...

The antilock system will be inoperative when towing with the engine/ignition off. It's a computer controlled thing, plus it needs control over the toads own brakes to do anything.

I wasn?t aware brakes could be adjusted for equality in lock up and will follow that up.
Click to expand...

Normal brake adjustment is to have all 4 wheels braking at the same level, but sometimes one gets out of adjustment or otherwise starts to do either more or less than  its share.  Any competent brake tech can make sure that all are braking the same. Once you are sure they are, then the M&G can't make one brake lock up any sooner than the rest, since it applies hydraulic pressure to the whole brake system at once.
 
I too had the M&G installed by techs in Athens, although not at the factory.

Just for clarification, the M&G applies air to push a piston between the vacuum booster and the master brake cylinder. There's no way it can apply hydraulic pressure to only one brake.
 
Right - the M&G does them all the same. However, the car's own system does not necessarily respond evenly, i.e. one brake may "grab" sooner than the others. If the M&G applies more braking than desirable, that "grabby" brake will lock before the rest.
 
My response was to clarify that it could not be the M&G system causing the problem, so it must be an issue with the car's braking system.
 
Did you pump the brakes to use up the vacuum in the brake booster before towing? Sounds like you need to dial back the pressure/brake force.
Bill
 
  I believe a leaking wheel cylinder/caliper can cause a brake to grab. At least it did on my Tracker, but that was just in ordiinary driving and I could certainly feel it.
 
MG has a brake line pressure adjuster that is installed before the MG unit.  The MG factory installed one for my rig.  Used the gravel road test to adjust.

Bill Dane
99 Country Coach

 
  The M&G  has the input after the booster,,the booster has no vacuum without the engine running and does not "store" vacuum.>>>Dan
 
utahclaimjumper said:
  The M&G  has the input after the booster,,the booster has no vacuum without the engine running and does not "store" vacuum.>>>Dan
Click to expand...
Well yes it will store vacuum. I have chirped the tiers on my CR-V when I forgot to pump the brakes after shutting the motor off before towing. That first stop leaving a campground can be interesting. I don't know how long the canister will hold vacuum but.
Bill
 
Don't have the M & G system, but my 2013 CRV stores vacuum unless I push on the break 2 or 3 times to release it.  A few weeks ago I forgot to do that and in Lone Pine I had to hit the breaks and the CRV came to a screeching stop like you described without causing any flat spots on the tires.  Dick nvrver
 
utahclaimjumper said:
Does your Honda manual tell you to do that?? If so the Honda is unique and daverb should have known that.>>>D
Click to expand...
Sorry Dan
Many cars store vacuum in the the booster. Some have a check valve on the vacuum hose going to the booster. They look like this.

https://www.walmart.com/ip/Dorman-Help-80190-Brake-Check-Valve/173650698?wmlspartner=wlpa&selectedSellerId=1148&adid=22222222227052480352&wmlspartner=wmtlabs&wl0=&wl1=g&wl2=c&wl3=152490426171&wl4=pla-263381516809&wl5=9022633&wl6=&wl7=&wl8=&wl9=pla&wl10=112562587&wl11=online&wl12=173650698&wl13=&veh=sem
 
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