Pulling to offside under braking

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rossbraithwaite
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Pulling to offside under braking

#1

Postby rossbraithwaite » Thu Oct 12, 2017 9:26 am

Hi All, As the title suggests my car has started pulling to the offside under braking. It varies in severity but under hard braking at low speed the steering wheel kicks round to the right. It has done this once before about 3 years ago and I refurbished the entire front end braking system. Didn't touch the read end except bleeding. This refurb included having my Dunlop calipers sleeved with stainless steel (although I was unable to inspect this).
Also, the front suspension has just been refurbed with new bushes and dampers. The car drives fine except under braking. Is this symptom 100% definitely near/offside brake balance related? How best to check the suspect nearside caliper?
Thanks,
Ross
'68 S1.5 FHC, manual, maroon with black interior. Originally exported to Arizona but 'repatriated' in '89. Since converted to RHD and triple SUs.

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cactusman
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Re: Pulling to offside under braking

#2

Postby cactusman » Thu Oct 12, 2017 12:51 pm

If it pulls to one side when rolling along with no brake application then it is probably a tracking/suspension issue. However if it rolls straight and only pulls when the brakes are applied it is probably a brake issue. Pulling to the offside suggests lack of brake effectiveness on the near side. This might be an air lock, sticking pistons in the caliper, worn discs and/or pads. From what you say everything is renewed so I would start by bleeding the system. Remove the pads and inspect for fluid leaks on to the pads and discs or even over enthusiastic grease applications when the suspension was rebuilt that has got on to the discs. Any evidence of grease will probably mean new pads and a good clean of the discs with brake cleaner. Any evidence of leaks from a piston and it will be off with the caliper. If all seems well and you are sure there is no air after bleeding it might be a stuck caliper piston.....not for the faint hearted but...You could ask an assistant around. Remove the near side pads and have the assistant VERY gently press the brake and check that both pistons evenly emerge a bit. Trouble is you will then have to lever them back in in order to refit the pads which can be a hugger....good luck and hope you find the issue..
Julian the E-type man
1962 FHC
1966 MGB....fab little car too

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Duckham
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Re: Pulling to offside under braking

#3

Postby Duckham » Thu Oct 12, 2017 3:28 pm

Also aggressive power on / power off can sometimes help highlight play in the suspension before tearing into things.
If you have a friendly MOT garage then putting the front wheels on the brake testers will confirm it is brake inefficiency. Putting the rear on is more debatable due to the LSD.
If it is the brakes then follow Julian's guide but I would replace the pads with a lever (even a suitable piece of wood) before pressing on the pedal to ensure the pistons don't come out too far.
An old flexi pipe could also be causing problems.
Joe
63 OTS

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Re: Pulling to offside under braking

#4

Postby cactusman » Thu Oct 12, 2017 3:56 pm

Good points Joe....yes...get to a friendly MOT man . I know that major corrosion around the rear training arm anchor points can cause hugely unpredictable behaviour if a joint pulls out but am guessing the car is pristine and rust free. Popping a squishy pipe in to replace the pads is a good wheeze when seeing if the pistons move :bigrin: :bigrin:
Julian the E-type man
1962 FHC
1966 MGB....fab little car too

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Re: Pulling to offside under braking

#5

Postby Hugo » Wed Oct 18, 2017 3:44 pm

Brake hoses. Little buggers. They block internally.
Hugo Miller - rebuilding an imported Series II OTS & converting to RHD

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keithmac
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Re: Pulling to offside under braking

#6

Postby keithmac » Sat Oct 21, 2017 3:09 pm

I have exactly the same problem. New rotors, new pads, new piston rubbers all round, new servo , new master, new flex hoses, calipers centered. Bled three times. STILL PULLS HARD TO THE RIGHT ON BRAKING.
Please let me know if you find a resolution to this
Thanks!
Early 1967 S1 OTS, 1952 MG TD

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Re: Pulling to offside under braking

#7

Postby 1954Etype » Sat Oct 21, 2017 4:16 pm

Swap the pads over. That will take one item out of the equation.
Angus 65 OTS 1E11497

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Re: Pulling to offside under braking

#8

Postby Hugo » Sun Oct 22, 2017 12:38 am

keithmac wrote:I have exactly the same problem. New rotors, new pads, new piston rubbers all round, new servo , new master, new flex hoses, calipers centered. Bled three times. STILL PULLS HARD TO THE RIGHT ON BRAKING.
Please let me know if you find a resolution to this
Thanks!



Does it snatch to the right when you touch the brakes, or does it get worse under heavy braking? If the former, it might just be a spot of brake fluid or grease on the RH pads, although it's difficult to envisage how that could have got there. If the latter, I would try clamping off the right front brake hose & see what happens. Logically it should pull hard to the left, but you never know....
It's definitely the front brakes that are out of balance I take it? From your description it sounds like it is, but never take these things for granted.
Hugo Miller - rebuilding an imported Series II OTS & converting to RHD

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keithmac
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Re: Pulling to offside under braking

#9

Postby keithmac » Tue Oct 24, 2017 12:44 am

Mine gets worse under hard braking and I confirm with an infrared sensor that the rear discs are the same temp after a good work out but the right front is 20 degrees hotter than the left. I am considering swapping the left and right calipers to see what happens as I feel like Iam running out of ideas and things to replace. I may try one brake bleed first though. I will report if I find a cause
Best regards
Early 1967 S1 OTS, 1952 MG TD

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Re: Pulling to offside under braking

#10

Postby Hugo » Tue Oct 24, 2017 2:13 am

Bleeding won't make any difference. Definitely start swapping parts over. I would start with the pads, & if that doesn't work, swap calipers as you suggest. Or just swap the whole lot over. Unless you have mis-matched pads, this sounds like a caliper issue. The good news is there are only a limited number of things it can be.
Hugo Miller - rebuilding an imported Series II OTS & converting to RHD

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Re: Pulling to offside under braking

#11

Postby JagWaugh » Tue Oct 24, 2017 8:40 am

keithmac wrote:Mine gets worse under hard braking and I confirm with an infrared sensor that the rear discs are the same temp after a good work out but the right front is 20 degrees hotter than the left. I am considering swapping the left and right calipers to see what happens as I feel like Iam running out of ideas and things to replace. I may try one brake bleed first though. I will report if I find a cause
Best regards

Presuming it is brakes, and at the front...

The temperature delta is a bit small (regardless of if that's C or F), but still, that would indicate either a caliper/cyl/pad sticking on, retracting slower, or dragging on the hotter side OR a caliper/cyl/pad not applying a braking force on the cold side.

Is the disc runout pretty much the same on both sides?
Are the pads pretty much all the same thickness?

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Re: Pulling to offside under braking

#12

Postby keithmac » Fri Oct 27, 2017 12:23 am

confirm run out is similar, Pads are new and identical..........
Early 1967 S1 OTS, 1952 MG TD

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Re: Pulling to offside under braking

#13

Postby cactusman » Fri Oct 27, 2017 12:42 pm

Not impossible that the pads are dodgy but pretty unlikely....unless contaminated in some way by oil or grease or the like. If the calipers are old then I would start with them. Strip them down. New seals and dust covers and possibly pistons if corroded. Careful reassembly and refit....Not hugely costly...just time and a pot of red rubber grease...
Julian the E-type man
1962 FHC
1966 MGB....fab little car too

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Re: Pulling to offside under braking

#14

Postby Hugo » Fri Oct 27, 2017 2:58 pm

I think he already did that; "I have exactly the same problem. New rotors, new pads, new piston rubbers all round, new servo , new master, new flex hoses, calipers centered. Bled three times."
Hugo Miller - rebuilding an imported Series II OTS & converting to RHD

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Re: Pulling to offside under braking

#15

Postby cactusman » Fri Oct 27, 2017 4:09 pm

One can only imagine then that there is some partial blockage in the pipe to the near side that is causing a pressure drop along the pipe significant enough to cause the near side caliper grip to be significant different. I would get it to an MOT man first and have them test the front brake force. If it turns out they are the same then it would point to some anomaly in the suspension geometry somewhere although I have no idea what...
Julian the E-type man
1962 FHC
1966 MGB....fab little car too

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Re: Pulling to offside under braking

#16

Postby mgcjag » Fri Oct 27, 2017 4:11 pm

Hi Keith.......it look like you have already ruled out the brakeing system and have checked everything......does the car steer straight ahead under normal driving....if it steers in one direction this will be exagerated under brakeing...have you looked at tracking, suspension , wheel bearings, wheels/tyres/spokes
Ross.....when you had the front bushes replaced.....was the ride height set correctly both sided..and the wishbone shaft nuts left loose and only tightened when the full weight of the car was let down......Steve
Steve
1969 S2 2+2 & Building a C type replica

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Re: Pulling to offside under braking

#17

Postby Hugo » Fri Oct 27, 2017 4:18 pm

cactusman wrote:One can only imagine then that there is some partial blockage in the pipe to the near side .


That was my initial suggestion. Never used to be a problem in the good old days, but they changed the manufacturing process to make the hoses impervious to water or some such, and since then they've been nothing but trouble. They now routinely act as one-way valves.
Hugo Miller - rebuilding an imported Series II OTS & converting to RHD

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Re: Pulling to offside under braking

#18

Postby JagWaugh » Fri Oct 27, 2017 4:58 pm

Hugo wrote:
cactusman wrote:One can only imagine then that there is some partial blockage in the pipe to the near side .


That was my initial suggestion. Never used to be a problem in the good old days, but they changed the manufacturing process to make the hoses impervious to water or some such, and since then they've been nothing but trouble. They now routinely act as one-way valves.


In that case the "good old days" must have ended about 1979, because I remember seeing then.

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Re: Pulling to offside under braking

#19

Postby cactusman » Fri Oct 27, 2017 5:45 pm

Have goodridge (spelling?) Braided Flexible Hoses on mine....seem fine....
Julian the E-type man
1962 FHC
1966 MGB....fab little car too

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Re: Pulling to offside under braking

#20

Postby Hugo » Fri Oct 27, 2017 6:20 pm

JagWaugh wrote:
Hugo wrote:
cactusman wrote:One can only imagine then that there is some partial blockage in the pipe to the near side .


That was my initial suggestion. Never used to be a problem in the good old days, but they changed the manufacturing process to make the hoses impervious to water or some such, and since then they've been nothing but trouble. They now routinely act as one-way valves.


In that case the "good old days" must have ended about 1979, because I remember seeing then.


Probably ;)
Hugo Miller - rebuilding an imported Series II OTS & converting to RHD

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