Front wheels locking up during hard braking

[ekslee]

1969 280 SL -
Front wheels seem to lock up and skid rather easily.  I'm suspicious that the back brakes aren't doing their share of the work.  How would I check? 

It's my Mom's car, so I don't drive it often (just to diagnose/fix).  Not sure if I've just gotten used to modern anti-locking braking systems, but when I was younger (decades ago), I used to marvel at good the Mercedes brakes were.   

Have changed master cylinder and both front calipers and lines in the last 5 yrs.  I read the on-line tech manual and it says brake hoses need to be changed about every 10 yrs, so I'm thinking I should change the rear brake hoses.  I also read about the brake force regulator.  I'm wondering if that could go bad and not deliver enough pressure to the rear brakes. 

Thoughts? 

[stickandrudderman]

Failed suspension components will cause this too.

[hkollan]

Changing the brake hoses if they are not recent is always useful as you suggest.
Also I suggest to check the condition and specifically the age of the tires.

[ekslee]

Thanks.  Will let you all know what happens. 
Interesting comment about the suspension.  Car has developed a misalignment and pulls to the right - wonder if that could be related. 
Tires are pretty old, but have lots of tread.  Will change brake hoses, first. 

[hkollan]

 How much thread is left has little to do with condition of the rubber and how the tires behave during braking.
 The rubber simply looses its original properties when it comes to friction, and will lead to braking results as you describe them after not too many years.

[stickandrudderman]

Car has developed a misalignment and pulls to the right - wonder if that could be related.

Therein lies the problem.
New brake hoses will make no difference to the fault you describe.