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MG TD TF 1500 - Brake Pedal Travel
|Itís been a few years since Iíve posted anything or even responded to other posts. But, rest assured, Iím still driving my TD. |
Hereís the most recent issue. I just had the brakes re-done: new shoes and rebuilt all cylinders. Before the brake work, the pedal didnít travel much before the shoes engaged. Now, the pedal moves about two inches until the brakes engage. I doubt thereís any air in the lines, as the brakes engage firmly. I checked the positions on all shoes, and theyíre right on. Braking action is fine, the issue is just that the pedal travels most of the way to the floor before the brakes engage. The shop said that this is normal TD and the way it should be.
So, hereís the question. Is there any adjustment on the brake pedal or other linkages to decrease the pedal movement before the brakes engage?
|Welcme back, Steve. Yes, there is adjustment in the brake pedal linkage, where the actuation rod enters the master cylinder. But, you shouldn't have to go there if you didn't do anything to the master cylinder. My best guess is that you have some air in the system that needs to be bled out. Bud
|Bud is right about the pedal adjustment. Shop manual says 1/2" freeplay before the pedal/linkage hits the piston. If it is going to near the floor something really badly wrong. If not air, shoes not adjusted tightly? They often really loosen after applying the first few times, check the adjustment of each shoe. George PS- new MC, or did you rebuild? Major problems with sticking pistons/incorrecct seals as Bud found out.|
|Steve, "The shop said that this is normal TD and the way it should be."|
What shop is this? Not normal for my car or any car I've ever driven!
"the pedal travels most of the way to the floor before the brakes engage"
but you also said:
"the pedal moves about two inches until the brakes engage"
Which is it? Or is your pedal 2" from the floor at rest?
In any case, something doesn't sound right. I redid mine during resto a year ago and this is not how mine work. I'm sure the real experts will chime in. It's Sunday and I hope they're out driving!
|I have learned some time ago that the brake cylinders are not easy to bleed . Therefore they should filled |
with a syringe of some sort with oil before you mount them on the back plate. After that done .. you start bleeding the whole system . The Mc should be bench bleed ed also . Right or wrong ?? but the above is stamped in my old brain .
I just went through your scenario about a month ago and had the same problem, and found a fix in the archives here. Sorry, I can't recall who should take credit, but it certainly isn't me.
Here's the solution: Fill each wheel cylinder with brake fluid from a syringe. You can do it before you install them on the backing plate, if you have some plastic plugs to put in the hole to keep the fluid in and the dirt out while installing them.
Others have filled them with a syringe while they're already on the backing plates, and simply reinstalled the brake line immediately. Its your choice.
Install all of the brake shoes, etc., and here's the secret ..... leave the brake adjusters set to zero. Do not adjust any of them until AFTER you have bled all of the cylinders.
That way the pistons each move further when you bleed them, expelling all of the air.
I was amazed at how much this one change in the bleeding sequence made. I now have very little travel in the brake pedal before the shoes grab, whereas before the pedal had to almost be to the floor.
|Thank God my old brain memory was still working when I wrote the message. Gene your remark make sense to leave the adjusters at zero .|
|Bud - Thanks for the suggestion and the picture. I'll pull the car out in the daylight tomorrow, crawl under it, and take a look.|
George - The 1/2 inch you mention probably is what I had before. Whatever travel I had before, it certainly was less than what I have now.
Ed - Sorry for the confusing statements. I didn't actually measure the travel, but it felt like the pedal moved about 2 inches, which is most of the way to the floor. Regardless, it just doesn't feel right.
Thanks to all for your quick replies.
This thread was discussed between 04/11/2012 and 05/11/2012
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