Intermittent weirdness

[roscoe]

I know when I figure this out it will be an "of course you moron" moment, but I havn't looked at anything yet and I'd like your opinion. Here it is. This happened once and the car drives normally in all respects as of parking it a few minutes ago. 56 BN-2, stock brakes, overdrive works peachy, smooth in all gears, doesn't have any gearbox problems. The scenario: Drove 25 mi to work. After work ran a few errands around town ((about 75 degrees outside, nice). Stopped at a four way and when I went to pull away (in 2nd gear) it behaved as if I was standing on the brakes. Seemed to shift in and out of all gears, tried reverse, same thing. I actually stalled it a couple of times with no movement of the wheels. Then, all of a sudden, everything was good again. Finsihed my errands, drove 25 miles home. No problems. I think I now realize it may have done this a couple of times in the 2000 miles since I finished the rebuild. It was much more short lived in that I had convinced myself I was mistakenly in top gear when I was trying to pull away from a stop. I fiddled with the shift and it was fine. Now after this, I'm not so sure sure I was in 4th. It was the same sort of lugging, or stuck brake feeling, but it went right away. I'm going to look at the brakes first, although the pedal felt normal when this was going on, I thought that somehow perhaps pressure from my stop had been trapped downstream of the master cylinder. When I got off the freeway and onto the rural roads I tried to make it happen again, but no such luck. Sitting in my chair here, that is my best guess. Any thoughts?

 

[GregW]

1st thought would be a bad rebuild on a brake booster, but you probably don't have one in the BN2. Next in line would be the flex line for the brakes. If they are old, they may have deteriorated from the inside and create a valve of sorts that blocks fluid from retreating back to the reservoir.

 

[roscoe]

Thanks greg. The brake lines are NOS. They looked dandy, but you could be right. I am also using DOT 5 (silicone) brake fluid. I certainly don't know the interaction between silicone fluid and new/old stock brake lines, but they do seem to work fine at the moment. My birthday is this month. I'll ask my wife to get me a set of stainless/teflon flex lines. Good idea anyway.

 

[Keoke]

NOS Brake lines do not like DOT 5 Brake fluid.---

OR: DOT 5 brake fkuid does mot like NOS Brake lines.---




-----------------------------------------Keoke------ :laugh:

 

[roscoe]

Well, I guess that about closes out this thread. I think I just posted something not too long ago in which I mentioned how trouble free my conversion to DOT 5 had been. If I'd only kept my mouth shut. When I change them and do an autopsy, I'll post on this subject again. Perhaps a doctor in the house could come up with a stent, or perhaps an automotive angioplasty device that would get me a few more miles on these.
I hate it when I get the little Keoke icon shaking it's head in the "no, no" direction.

 

[Genos2]

Sometimes if the master cylinder actuating rod is adjusted too tightly, (should be about a 1/32 play at top of pedal) as fluid heats and expands it will tighten the distance between the two.Quite common on older cars w/adjustable rod.Also happens on newer cars w/booster& rod misadjusted on booster. Can be checked by feeling for play after good hard run or jacking up & checking wheels for ease of movement. cheers Geno

 

[roscoe]

Hey, another west coast guy with a good idea (especially good because it is an easy adjustment). I'm off for the night. Maybe I'll get to see if the east coast agrees tomorrow. Thanks.

 

[stevebn2bj7]

I had a similar experience this past weekend that resulted in my first trip home on a flatbed in the BJ7. Inadvertantly dumped the clutch at a stop with foot on the brake and in first gear. Not the first time this kind of thing has happened in this or other cars. Motor started right up and when I let the clutch out it tried to move and stopped again. Kinda like having a brake stuck on or stnading on the brake pedal. It would not brake free and would not move even in neuteral. Disconnected drive shaft to get it home. Once back in the garage I was able to get the tranny free by working the tailshaft a bit. Was having trouble with the 2-3 synchro and maybe that let go. Nothing mettalic came out of the tranny with a magnet. However, the oil looks a bit like metallic paint. Fortunately have a spare top shifter and will swap it out once I replace the seals, clean it and paint it. Will take the current one out for a spin this weekend to see if the o/d still works then swap it out. Someday when I get time I will take it apart and see what happened.

 

[nevets]

I seem to recall a thread about rubber seals and silicone brake fluid, or was it an article in one of the Healey club magazines? Anyway, I think there was some mention about seals swelling and causing problems such as mentioned by roscoe.

 

[zblu]

The only time I ever dumped the clutch with lots of revs decades ago as a kid the front corner went way up, the clutch plate turned into vacuum cleaner dust, and I sheared an axle right in between the bearings, what a pain to fix!

 

[stevebn2bj7]

This was not a high rev dump, just an idle or little higher dump. The kind of thing you do when learning how to drive.

 

[Patrick67BJ8]

This was not a high rev dump, just an idle or little higher dump. The kind of thing you do when learning how to drive.

"Just a little higher dump"??? I wish you could have seen my sister learning to drive our family Falcon station wagon back in the 60's! It was a standard practice to start a person out <span style="text-decoration: underline">learning to drive</span> with a clutch type of car.
Patrick

 

[bt7tricarb]

In response to your birthday request...

I have the stainless lines on the front, but not on the rear. I ordered the complete kit (from either Cape, I think) but for some reason the rear line was faulty.

Not trying to discourage you from using it on yours and I'm sure many people have had success with them, but I just thought I'd mention it...

 

[TomFromStLouis]

Sorry to be so slow, but could someone define "dumping the clutch"? Does this mean the clutch somehow no longer engages and just pumps freely without resistance or effect? What do revs have to do with this phenomenon?

Just trying to keep up on the learnin'....

 

[Keoke]

Sorry to be so slow, OH thats OK!

but could someone define "dumping the clutch"? Does this mean the clutch somehow no longer engages and just pumps freely without resistance or effect

---NO Tom, Just Imagine you are about to pull off and your foot accidently slips off the clutch petal [ Dumping the Clutch ] and the car subsequently jerks or lurches forward.

What do revs have to do with this phenomenon?---Well

The higher the Revs the more shock is transmitted to the drive train and possibly your pocket book.. :laugh:

Just trying to keep up on the learnin'....

 

[Ed_K]

Instead of DOT-5 ( silicone ), use DOT-4 Castrol LMA ( synthetic but not silicone ). I use it in my daily drivers as well. It is Good stuff I.M.H.O.
Ed

 

[stevebn2bj7]

Took my BJ7 out for a spin yesterday after getting the tranny freed up last week. It worked as it did before, shifted fine except that 2-3rd shift where it does not smoothly go into 3rd unless you go very slowly. Overdrive worked fine. My only guess is that the synchro is gone and something from that got jammed in there last weekend and freed itself up when I was fiddling with it. Still going to swap out the tranny but any thoughts or insight on what may have caused the lock up would be greatly appreciated.

 

[RonMacPherson]

All brake fluids are synthetic.

Dot 3,4 and 5.1 are ester based. Dot 5 is silicone based.

Now as far as compatibility with nos seals go, I would recommend ONLY CAstrol LMA or Castrol Blue if you are using seals that are not made to modern composition specs.

If you have any "new" rubber for brake systems, that is not more than 5 years old, and is made here in the USofA, by federal mandate it has to be compatible with silicone formulations.

Silicone brake fluid does NOT eat paint and does NOT absorb water... I recommend it, whenever you can use it.

 

[roscoe]

I rebuilt all of my slave cylinders when I did my restoration. I had several seeps and drips from them for a couple of months after servicing. I was not happy , but was willing to give what-ever magic "swelling"agents are in the DOT 5 fluid a chance. The brakes dried up, I haven't lost a drop of fluid in a year and a half. Brake function was always good, until the incident that started this thread. Bear in mind once things got moving again they have been fine ever since. I still am not certain it was a brake problem, but my teflon/stainless flex lines are on the way.

 

[pan]

I have had a similar thing happen to me. On this occasion, I had returned to the car from a short errand and noticed that the tail lights were glowing. I couldn't remember switching on the lights as it was broad daylight, but I went to switch them off anyway, and they were off!
It was the brake lights that were glowing. A quick pump of the pedal released the brakes.
What had happened was that the the master cylinder piston had jammed due to wear in the cylinder bore.